Rubber compositions containing small particle size zeolites

ABSTRACT

Rubber compositions which contain zeolite particles having particle sizes of no more than 1.6 microns in diameter with at least 90% of the weight of the particles being between 0.1 and 3.2 microns in diameter, a binding agent, water, and a solubilizing agent.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of copending U.S. applicationSer. No. 557,377, filed Dec. 1, 1983 now abandoned; which is acontinuation of Ser. No. 349,787, filed Feb. 18, 1982, now abandoned;which is a continuation of Ser. No. 093,345, filed Nov. 21, 1979, nowabandoned; which is a continuation-in-part of Ser. No. 088,243, filedOct. 25, 1979, now abandoned; which is a continuation-in-part of Ser.No. 971,584, filed Dec. 20, 1978, now U.S. Pat. No. 4,235,836. Thisapplication is also a continuation-in-part of copending application Ser.No. 572,122, filed Jan. 17, 1984 now abandoned; which is a continuationof Ser. No. 274,898, filed June 18, 1981, now abandoned; which is acontinuation-in-part of Ser. Nos. 093,345, 088,243, and 971,584,previously listed, and which said application Ser. No. 274,898 is also acontinuation-in-part of copending application Ser. No. 189,419, filedSept. 22, 1980 now abandoned, which is a continuation-in-part of Ser.Nos. 093,345, 088,243, and 971,584, previously listed.

TECHNICAL FIELD

The present invention relates to the production of zeolites and, morespecifically, to processes for the production of zeolites of small anduniform particle size, processes for making zeolite Y, and compositionscontaining these zeolites.

BACKGROUND ART

Naturally occurring hydrated metal aluminum silicates are calledzeolites and are well known in the art as synthetic absorbents. The mostcommon of these zeolites are sodium alumino zeolites. Zeolites consistbasically of a three-dimensional framework of SiO₄ and AlO₄ Tetrahedra.The tetrahedra are cross-linked by the sharing of oxygen atoms so thatthe ratio of oxygen atoms to the total of the aluminum and silicon atomsis equal to two or 0/(Al+Si)=2. The electrovalence of each tetrahedracontaining aluminum is balanced by the inclusion in the crystal of acation, for example, a sodium ion. This balance may be expressed by theformula Al₂ /Na₂ =1. The spaces between the tetrahedra are occupied bywater molecules prior to dehydration. The main products of these typesare known in the art as zeolite A, zeolite X, and zeolite Y.

Zeolites A, X, and Y may be distinguished from other zeolites andsilicates on the basis of their x-ray powder diffraction patterns andcertain physical characteristics. The composition and density are amongthe characteristics which have been found to be important in identifyingthese zeolites.

The basic formula for all crystalline sodium zeolites may be representedas follows:

    Na.sub.2 O:Al.sub.2 O.sub.3 :xSiO.sub.2 :yH.sub.2 O

wherin the values for x and y fall in a definite range. The value x fora particular zeolite will vary somewhat since the aluminum atoms and thesilicon atoms occupy essentially equivalent positions in the lattice.Minor variations in the relative numbers of these atoms does notsignificantly alter the crystal structure or physical properties of thezeolite. For zeolite A, an average value for x is about 1.85 with the xvalue falling within the range 1.85±0.5. For zeolite X, the x valuefalls within the range 2.5±0.5.

The formula for zeolite A may be written as follows:

    1.0±0.2Na.sub.2 O:Al.sub.2 O.sub.3 :1.85±0.5SiO.sub.2 :yH.sub.2 O

The formula for zeolite X may be written as follows:

    0.9±0.2Na.sub.2 O:Al.sub.2 O.sub.3 :2.5±SiO.sub.2 :yH.sub.2 O

The formula for zeolite Y may be written as follows:

    0.9±0.2Na.sub.2 O:Al.sub.2 O.sub.3 :4.5±1.5SiO.sub.2 :yH.sub.2 O

wherein y may be any value up to 6 for zeolite A, any value up to 8 forzeolite X, and any value up to 9 for zeolite Y.

In zeolites synthesized according to the preferred art procedure, theratio sodium oxide to alumina should equal one. But if all the excesssodium present in the mother liquor is not washed out of theprecipitated product, analysis may show a ratio greater than one, and ifthe washing is carried too far, some sodium may be ion exchanged byhydrogen, and the ratio will drop below one. It has been found that dueto the ease with which hydrogen exchange takes place, the ratio forzeolite A lies in the range of ##EQU1## Thus the formula for zeolite Amay be written as follows:

    1.0±0.2Na.sub.2 O:Al.sub.2 O.sub.3 :1.85±0.5SiO.sub.2 :yH.sub.2 O

Zeolite A is disclosed and claimed in U.S. Pat. No. 2,882,243, entitled"Molecular Sieve Adsorbents," issued to Robert M. Milton on Apr. 14,1959. This patent discloses a process for producing zeolite A wherein asodium-aluminum-silicate water mixture is prepared having a water tosodium oxide ratio of from 35:1 to 200:1, a sodium oxide to silica ratioof from 0.8:1 to 3:1, and a silica to alumina ratio of from 0.5:1 to2.5:1. This mixture is maintained at a temperature of from 20 to 175degrees Celsius until zeolite A is formed.

The particle size of a zeolite affects the x-ray diffraction pattern ofthat zeolite. When the particle size of a zeolite is reduced, theintensities of peak heights in the zeolite's x-ray diffraction patternis also reduced. The x-ray diffraction pattern does not change, exceptthat the intensity of each peak height is reduced.

The identity of a zeolite of small particle size can be determined bycomparison of its x-ray diffraction pattern with that of a standardzeolite. The patterns should match, except that the intensities of thepeak heights of the pattern of the small particle size zeolite will besmaller than the intensities of the peak heights of the pattern of thestandard zeolite.

The particle size of zeolites is discussed in Breck, D. W. ZeoliteMolecular Sieves. N.Y., John Wiley & Sons, 1974, pgs. 384-388.TP159.M6B7. He states that particle sizes of the individual crystals ofzeolite range from 1 to 10 microns. He shows the particle sizedistribution of a typical zeolite sodium A powder having a weightaverage diameter of 2.78 microns and shows a histrogram of the particlesize distribution of a zeolite A preparation. From the histrogram it canbe seen that less than 35% of the particles have a diameter of less than2 microns.

The particle size of zeolites is also discussed in Meier andUytterhoeven Molecular Sieves, 1973, pgs. 169-178. This book shows arelationship between the crystal diameter and the water to sodium oxideratio. It also shows the influence of the silica source oncrystallization time.

Zeolite A and its method of preparation is also described in thefollowing U.S. Patents wherein the invention resides in the method ofpreparation.

U.S. Pat. No. 2,982,612

U.S. Pat. No. 3,058,805

U.S. Pat. No. 3,101,251

U.S. Pat. No. 3,119,659

U.S. Pat. No. 4,041,135

The oxide ratios for zeolite A production in the above patents is asfollows:

    ______________________________________                                        PRIOR ART OXIDE RATIOS FOR MAKING ZEOLITE A                                          Water/      Sodium Oxide/                                                                             Silica/                                                                              Tempera-                                Patent Sodium Oxide                                                                              Silica      Alumina                                                                              ture                                    ______________________________________                                        2,882,243                                                                            35-200      0.8-3       0.5-2.5                                                                              20-175                                  2,982,612                                                                            130-300     0.3-1       4-6    60-110                                  3,058,805                                                                            25-200        1-3       0.5-1.3                                                                              20-175                                  3,058,805                                                                            35-200      0.8-3       1.2-2.5                                                                              20-175                                  3,058,805                                                                            ?           ?           0.5-4.5                                                                               80                                     3,101,251                                                                            35-200        1.3-2.5   0.8-3  20-120                                  3,119,659                                                                            20-100        0.5-1.5   1.6-2.4                                                                              20-175                                  4,041,135                                                                            35-200      0.8-3       0.5-2.5                                                                              70-180                                  ______________________________________                                    

From the prior art, one would assume that zeolite A could not be madefrom a reaction mixture having a water to sodium oxide molar ratio ofless than 35:1 and a silica to alumina molar ratio greater than 2.4:1.Moreover, none of the above patents teaches a method of forming zeoliteA of small and uniform size having a high magnesium carbonate exchangecapacity.

The literature also indicates that the apparent pore diameter of zeoliteA is between 3.6 and 4.0 angstroms, depending on temperature. At liquidnitrogen temperature (-195.4 degrees Celsius), the pore diameter issmallest and prevents nitrogen from being adsorbed into the crystal. Forexample, as pointed out by Breck, D. W. Zeolite Molecular Sieves, NewYork, John Wiley & Sons, 1974, pages 634-639, at 635; "NaA adsorbs C₂ H₄(slowly) and CH₄, σ=3.9 and 3.8A, respectively. At low temperatures, itdoes not adsorb N₂. The apparent pore diameter is 3.6 to 4.0A, dependingon temperature. The explanation for this variation has been based upon aprocess of activated diffusion. It has also been postulated that thermalvibration of the oxygen ions, and cations, in the zeolite latticesurrounding the apertures is responsible."

Further, as pointed out in Milton U.S. Pat. No. 2,882,243, at column 13;

"The activated sodium zeolite A adsorbs water readily and adsorbs inaddition somewhat larger molecules. For instance, at liquid airtemperatures it adsorbs oxygen but not appreciable amounts of nitrogenas shown below for a typical sodium zeolite A sample.

    ______________________________________                                                             Partial   Weight percent                                         Temperature  pressure  adsorbed                                       Adsorbate                                                                             (°C.) (mm. Hg)  on Na.sub.2 A                                  ______________________________________                                        Oxygen  -196         100       24.8                                           Nitrogen                                                                              -196         700        0.6                                           ______________________________________                                    

DISCLOSURE OF THE INVENTION

It is an object of this invention to produce zeolites which have veryhigh exchange capacity for both calcium and magnesium ions, and rapidcalcium ion depletion rates which are superior to similar existingzeolites.

Another object of this invention is to produce zeolites of controlledparticle size which are useful as ion exchange materials in watersoftening compositions and detergents; as fillers in paper, rubber, andplastics; and as non-settling flatting pigments

In one aspect the present invention provides processes for theproduction of zeolites of small and uniform size and having highmagnesium exchange capacities characterized by the following steps:

(a) forming an aqueous solution of sodium aluminate;

(b) forming an aqueous solution of sodium silicate;

(c) mixing said sodium aluminate and said sodium silicate solutions at atemperature of 40° to 120° C.;

(d) reacting said mixed sodium silicate and sodium aluminate at atemperature slightly higher than said mixing temperature, the reactionmixture having the following molar ratios of components:

(1) water to sodium oxide 10:1 to 35:1

(2) sodium oxide to silica 1:1 to 4:1

(3) silica to alumina 1:1 to 10:1

(e) continuing the reaction at these molar ratios to form the zeolitewhile controlling the molar ratios and reaction time to produce a fineparticle size zeolite having an average particle size of less than 2microns in diameter; and

(f) recovering the zeolite.

In one embodiment of the invention, zeolites of small and uniform sizehaving a high magnesium exchange capacity are formed when the reactionmixture has a water to sodium oxide molar ratio of between 10:1 and35:1, preferably between 15:1 and 20:1, most preferably about 20:1; asodium oxide to silica molar ratio of between 1:1 and 4:1, preferablybetween 1:1 and 2.5:1, more preferably between 1.5:1 and 2:1, mostpreferably about 2:1; and a silica to alumina molar ratio of between 1:1and 10:1, preferably between 1.4:1 and 10:1, more preferably betweenabove 2.0:1 and 4.5:1, more preferably between 3:1 and 8:1, mostpreferably about 3:1. In a separate embodiment, when the sodium oxide tosilica molar ratio is less than 3, the silica to alumina molar ratio isat least 1. When the sodium oxide to silica molar ratio is at least 4:3,the sodium oxide to alumina molar ratio is at least 4:1. Further, whenthe SiO₂ :Al₂ O₃ molar ratio is 2.0:1 or below, the maximum temperatureof reaction is about 80° C. Also, as this ratio decreases, the number ofcombinations of variables decreases.

The present invention involves the production of zeolites of small anduniform size having characteristics typical of known zeolites but alsohaving a high exchange capacity for both calcium and magnesium ions, anda rapid calcium ion depletion rate which is superior to similarzeolites. These zeolites are produced without the use of mechanicalmethods such as high shear agitation or grinding of the product. Thezeolites of the invention in one embodiment are similar to zeolite A inchemical formula and x-ray diffraction pattern but different fromzeolite A in having depressed peak intensities in the x-ray diffractionpattern, in having unexpectedly high magnesium exchange capacity, and inhaving larger ports or pore size diameters than zeolite A.

In a main embodiment of the present invention, zeolite particles ofsmall and uniform average particle size of no more than 3.5 microns withat least 90% of the weight between 0.1 and 6.0 microns, and having ahigh magnesium exchange capacity, are produced by forming a sodiumaluminate solution, forming a sodium silicate solution, mixing thesodium aluminate solution and the sodium silicate solution to form areaction mixture comprising either a sodium silicate, sodium aluminate,or sodium hydroxide mother liquor, and an amorphous sodiumaluminosilicate which contains the following molar ratios of sodiumoxide (Na₂ O) to silica (SiO₂), silica (SiO₂) to alumina (Al₂ O₃), andwater (H₂ O) to sodium oxide (Na₂ O):

Na₂ O: SiO₂ =1.2:1 to 10.0:1

SiO₂ :Al₂ O₃ =1.0:1 to 7.3:1

H₂ : Na₂ =10:1 to 30:1;

heating the reaction mixture to a temperature of from 40 to 120 degreesCelsius, more preferably from 60 to 120 degrees Celsius, most preferably60 degrees Celsius, and reacting until a zeolite is formed, thenrecovering that zeolite; wherein, in the reaction, said molar ratios andreaction temperatures are chosen from the values provided so as toproduce zeolites of average particle size in microns whose natural log(ln) is in accordance with the following equation:

    ______________________________________                                        Average ln                                                                            =     A(N/S × S/A) + B(H/N × Temp/100) +                  (Particle     C(S/A).sup.3 + D(S/A).sup.2 + E(H/N ÷ S/A) +                Size)         F(S/A) + G(Temp/100).sup.3 + H(H/N ÷ N/S) +                               I(N/S).sup.2 + J(N/S ÷ S/A) + K                             ______________________________________                                    

wherein:

H/N--Moles of H₂ O÷moles Na₂ O present in the batch;

N/S--Moles Na₂ O÷moles SiO₂ present in the batch;

S/A--Moles SiO₂ →moles Al₂ O₃ present in the batch;

Temp - Reaction temperature in degrees Celsius at which the batch isheld until crystallization is complete;

and A, B, C, D, E, F, G, H, I, J, and K are constants having thefollowing values:

A=-0.14827

B=0.11922

C=-0.03245

D=0.59054

E=-0.10945

F=-3.31907

G=0.50955

H=0.00532

I=0.12626

J=-0.76339

K=5.40831.

Both the sodium aluminate solution and the sodium silicate solution arepreferably preheated to a temperature of between 40 and 120 degreesCelsius prior to mixing and more preferably 80 degrees Celsius. In apreferred procedure, the sodium aluminate solution is rapidly added tothe sodium silicate solution so that alI of the sodium aluminatesolution is added in a period of about 30 seconds to about 30 minutes,depending on the volume. The mother liquor can be recycled as a sourceof sodium and silica, if suitable. Thus at a batch concentration of SiO₂/Al₂ O₃ of 2.0, the mother liquor is NaOH and contains no appreciableSiO₂ or Al₂ O₃, and at a batch concentration of SiO₂ /Al₂ O₃ of lessthan 2.0 the mother liquor contains sodium and aluminum, and at a batchconcentration of SiO₂ /Al₂ O₃ of greater than 2.0, the mother liquorcontains sodium and silica. The reaction mixture is provided with goodagitation to ensure good mixing.

According to further features of the present invention, there areprovided zeolite particles of generally small and uniform size whichhave average particle sizes of less than about 3.5 microns, preferablyless than about 2.0 microns, having a magnesium exchange capacity ofgreater than about 90 mg, preferably about 140 mg MgCO₃ /g of zeolite, acalcium carbonate exchange capacity of greater than about 230 mg CaCO₃/g of zeolite, a port size or pore diameter greater than conventionalzeolite A in that the particles have the capacity to absorb nitrogeninto the crystal structure, an x-ray diffraction pattern essentially thesame as zeolite A except that the peak intensities in the pattern aredepressed from that of a 4 micron zeolite standard, and a surface areaof greater than 10 m² /g and preferably in the range of 10 to 176 m² /g,said products being characterized in that said average particle sizes ofless than 3.5 microns are produced from a batch reaction mixturecomprising sodium silicate, sodium aluminate, or sodium hydroxide motherliquor and an amorphous sodium alumino silicate, in total having a waterto sodium oxide molar ratio of between 10:1 and 30:1; a sodium oxide tosilicate molar ratio of between 1.2:1 and 10.0:1, and a silica toalumina molar ratio of between 1.0:1 and 7.3:1, wherein said mixture isreacted at a temperature of about 60 degrees Celsius to 120 degreesCelsius; wherein said molar ratios and reaction temperature are chosenfrom the values provided so as to produce zeolite particles of averageparticle size in microns of less than 3.5 and preferably less than 2.1in accordance with the following equation where ln is natural log:

    ______________________________________                                        Average 1n =                                                                               A(N/S × S/A) + B (H/N × Temp/100) +                  (Particle Size)                                                                           C(S/A).sup.3 + D(S/A).sup.2 +                                                 E(H/N ÷ S/A) + F(S/A) +                                                   G(Temp/100).sup.3 + H(H/N ÷ N/S) +                                        I(N/S).sup.2 + J(N/S ÷ S/A) + K                               ______________________________________                                    

wherein:

H/N--Moles of H₂ O→moles Na₂ O present in the batch;

N/S--Moles Na₂ O→moles SiO₂ present in the batch;

S/A--Moles SiO₂ →moles Al₂ O₃ present in the batch;

Temp--Reaction temperature in degrees Celsius at which the batch is helduntil crystallization is complete and where A to K are constants asabove;

and provided further that said surface areas of greater than about 10 m²/g are obtained by selecting said molar ratios and reaction temperaturefrom the values provided so that the measured surface area is a functionof synthesis conditions and is expressed mathematically by the followingequation:

    ______________________________________                                        Surface area, =                                                                           A(H.sub.2 O/Na.sub.2 O) + B(Na.sub.2 O/SiO.sub.2) +               m.sup.2 /g C(SiO.sub.2 /Al.sub.2 O.sub.3).sup.2 + D(SiO.sub.2 /Al.sub.2                  O.sub.3).sup.3 +                                                              E(Temp).sup.2 + F(H.sub.2 O/Al.sub.2 O.sub.3) +                               G(H.sub.2 O/Al.sub.2 O.sub.3).sup.2 + H(H.sub.2 O/Al.sub.2                    O.sub.3).sup.3 +                                                              I(H.sub.2 O/Na.sub.2 O × Temp.) + J(SiO.sub.2 /Al.sub.2                 O.sub.3 ×                                                               Temp.) + K(H.sub.2 O/Na.sub.2 O ÷ Na.sub.2 O/SiO.sub.2) +                 L(H.sub.2 O/Na.sub.2 O ÷ SiO.sub.2 /Al.sub.2 O.sub.3) +                   M(Na.sub.2 O/SiO.sub.2 ÷ SiO.sub.2 /Al.sub.2 O.sub.3)          ______________________________________                                                   +N                                                             

wherein:

    ______________________________________                                        A =     -57.11009845  H =     2.6067484 × 10.sup.-5                     B =    -113.11000549  I =     0.13123613                                      C =     -65.39277171  J =     1.86829830                                      D =      4.76134125   K =     33.33057224                                     E =     -0.04384689   L =     14.30545704                                     F =      9.69234350   M =     93.07457393                                     G =     -0.02585795   N =    233.29360457                                     ______________________________________                                    

wherein:

H₂ O=Total moles of H₂ O in the batch

Na₂ O=Total moles of Na₂ O in the batch

SiO₂ =Total moles of SiO₂ in the batch

Al₂ O₃ =Total moles of Al₂ O₃ in the batch

Temp.=Temperature in degrees Celsius at which the batch is held untilcrystallization is complete

According to this invention, zeolites of small and uniform size having ahigh magnesium exchange capacity are formed when the reaction mixturehas a water to sodium oxide molar ratio of between 10:1 and 30:1,preferably between 15:1 and 20:1, most preferably about 20:1; a sodiumoxide to silica molar ratio of between 1.2:1 and 10.0:1, preferablybetween 1.5:1 and 2.5:1, most preferably about 2.4:1; and a silica toalumina molar ratio of between 1.0:1 and 7.3:1, preferably between 1.4:1and 4.5:1, most preferably about 2.0:1 for detergent production.

The particle size of the zeolite similar to zeolite A may be controlledby adjusting the silica to alumina molar ratio, with the particle sizedecreasing as the silica to alumina molar ratio is increased and theparticle size increasing as the silica to alumina molar ratio isdecreased. The particle size can also be controlled by adjusting eitherthe sodium oxide to alumina molar ratio or the alumina concentration,with the particle size decreasing as the sodium oxide to alumina molarratio is increased or the alumina concentration is decreased, and theparticle size increasing as the sodium oxide to alumina molar ratio isdecreased or the alumina concentration is increased.

This zeolite has a calcium carbonate exchange capacity greater than 230mg calcium carbonate per gram zeolite and a magnesium carbonate exchangecapacity greater than 90, and preferably greater than 120 mg magnesiumcarbonate per gram zeolite. The resulting particles exhibit a narrowdifferential weight percent gaussian distribution with an averageparticle size of no more than 2.1 microns with at least 90% of theweight between 0.1 and 4.0 microns, wherein the cumulative percentpopulation exhibits at least 35% less than one micron, with no more than5% greater than 5 microns.

This zeolite most preferably has a calcium carbonate exchange capacitygreater than 250 mg calcium carbonate/g zeolite and a magnesium exchangecapacity greater than 140 mg carbonate/g zeolite. It has 90% of theparticles less than 2 microns. The resulting zeolite particlespreferably exhibit a narrow differential weight percent gaussiandistribution with an average particle size of no more than 1.6 micronswith at least 90% of the weight between 0.1 and 4.0 microns, wherein thecumulative percent population exhibits at least 64% less than onemicron, with no more than 1% greater than 2.0 microns. It is useful asan ion exchange material in water softening compositions and detergents;as a filler in paper, rubber and plastics; and as a non-settlingflatting pigment.

The small particle size zeolites of the present invention, are similarto zeolite A of the prior art discussed above. Thus, the chemicalformula for the zeolites of the invention is essentially the same asthat recognized by the art for zeolite A. This formula is as follows:

    1.0±0.2Na.sub.2 O:Al.sub.2 O.sub.3 :1.85±0.5SiO.sub.2 :yH.sub.2 O

where y has a value of up to 6.

In addition, the x-ray diffraction pattern shows peaks in the sameregions as zeolite A but the peaks are depressed from those of zeoliteA. A substantial distinction is found in the fact that the zeolites ofthis invention have larger ports or pore diameters and thus increasedsurface areas when compared with zeolite A. The zeolites disclosed andclaimed herein are thus described as modified zeolite A particles.

The concept of increased pore diameter in small particle size modifiedzeolite A is supported by surface area measurements. Since thesemeasurements are based on nitrogen adsorption at -195 degrees Celsiusand nitrogen is theoretically too large to enter the zeolite A cages,only external surface area should be measured. For zeolite A with anaverage diameter of 1 μm, surface area by this technique should be about3 m² /g. In general, one finds that the measured surface area increasesdramatically when the average particle size is less than twomicrometers. Below this size, surface areas in excess of 100 m² /g arenot unusual. In order to obtain such hugh surface areas, the porediameter of the zeolite must have increased. This would permit nitrogento enter the crystal and begin to reflect internal surface area which isestimated to be in excess of 600 m² /g.

A most surprising and significant improvement found in smaller particlesizes of zeolite was an increased magnesium exchange rate. This wasunexpected because large particle size zeolite A as described in U.S.Pat. No. 4,041,135, exchanges only 49 mg MgCO₃ /g in 15 minutes but canreach 160 mg MgCO₃ /g in 24 hours. The literature frequently cites thisas a major inadequacy in detergent formulations. The acceptedexplanation of low magnesium exchange in zeolite A is related to thepore diameter of the zeolite relative to the larger diameter of thehydrated magnesium ion. Simply stated, the rate and apparent Mg⁺⁺capacity is limited by the fact that the hydrated magnesium ion hasdifficulty diffusing through the pores of the zeolite. Since the smallparticle size zeolite can achieve exchange capacities of 140-160 mg/g in15 minutes, it appears clear that the pore diameter of the zeolite isincreased over that of zeolite A.

In an interesting aspect, the zeolite particles of the invention werefound to have bimodal pore size distribution. This may be the reason thezeolites of the invention can absorb gases which are not absorbed bysimilar types of zeolites.

In a further embodiment, a zeolite similar to zeolite X of small anduniform size having a high magnesium exchange capacity is formed whenthe reaction mixture has a water to sodium oxide molar ratio of between30:1 and 60:1, most preferably about 30:1; a sodium oxide to silicamolar ratio of between 1:1 and 3:1, preferably between 1.2:1 and 1.7:1,most preferably about 1.6:1; and a silica to alumina molar ratio ofbetween 5:1 and 10:1, preferably between 6:1 and 8:1, most preferablyabout 7.3:1.

This zeolite has a calcium carbonate exchange capacity greater than 205mg calcium carbonate per gram zeolite and a magnesium exchange capacitygreater than 130 mg magnesium carbonate per gram zeolite, with theresulting zeolite particles exhibiting a narrow differential weightpercent gaussian distribution with an average particle size of no morethan 2.2 microns with at least 90% of the weight between 0.1 and 5.0microns, wherein the cumulative percent population exhibits at least 41%less than one micron, with no more than 5% greater than 3.2 microns.

This zeolite preferably has 90% of the particles less than 2 microns. Itpreferably has a calcium carbonate exchange capacity greater than 230 mgcalcium carbonate/g zeolite and a magnesium carbonate exchange capacitygreater than 135 mg magnesium carbonate/g zeolite. It is useful as anion exchange material in water softening compositions and detergents; asa filler in paper, rubber and plastics; and as a non-settling flattingpigment.

In still a further embodiment, a combination of from 20 to 80% of azeolite similar to zeolite X and from 20 to 80% of a zeolite similar tozeolite A is formed when the reaction mixture has a water to sodiumoxide molar ratio of between 10:1 and 60:1, preferably between 20:1 and50:1, more preferably between 25:1 and 35:1, most preferably about 30:1;a sodium oxide to silica molar ratio of between 0.5:1 and 3:1,preferably between 1.4:1 and 3:1, more preferably between 1.6:1 and 2:1,most preferably about 1.7:1; and a silica to alumina molar ratio ofbetween 2:1 and 15:1, preferably between 2:1 and 10:1, more preferablybetween 2:1 and 8:1, most preferably about 5.3:1.

This combination of these zeolites similar to zeolite A and zeolite Xhas a carbonate exchange capacity greater than 220 mg calcium carbonateper gram zeolite and a magnesium exchange capacity greater than 115 mgmagnesium exchange capacity greater than 115 mg magnesium carbonate pergram zeolite, with the resulting zeolite particles exhibiting a narrowdifferential weight percent gaussian distribution with an averageparticle size of no more than 5.4 microns with at least 90% of theweight between 0.1 and 10.0 microns, wherein the cumulative percentpopulation exhibits at least 37% less than one micron, with no more than5% greater than 5 microns.

This combination of these zeolites similar to zeolite A and zeolite Xpreferably has 90% of the particles less than 2 microns. It preferablyhas a calcium carbonate exchange capacity greater than 230 mg calciumcarbonate/g zeolite and a magnesium exchange capacity greater than 135mg magnesium carbonate/g zeolite. It is useful as an ion exchangematerial in water softening compositions and detergents; as a filler inpaper, rubber and plastics; and as a nonsettling flatting pigment.

In the following discussion the zeolites of this invention which aresimilar to zeolite A, zeolite X and zeolite Y, are referred to aszeolite A, zeolite X and zeolite Y for convenience. As pointed out abovehowever, the zeolites of this invention are different from zeolite A,zeolite X and zeolite Y of the prior art.

In a still further embodiment of the present invention, zeolite Y isproduced by dissolving sand in a sodium hydroxide solution at a pressureof at least 100 psig, preferably 140 psig; heated to a temperature of atleast 130° C., activating the sodium silicate thus formed with alumina,forming a sodium aluminate solution, adding sodium aluminate solution tothe sodium silicate solution so that all of the sodium aluminatesolution is added within 30 seconds to form a reaction mixturecomprising a sodium silicate mother liquor and an amorphous sodiumalumino silicate pigment having, in total, a certain composition,heating the mixture to a temperature of from 80° to 120° C., reactingthe mixture at a temperature of from 80° to 120° C., then recovering thezeolite produced. The sodium silicate solution has a silica to sodiumoxide molar ratio of between 2.4:1 and 2.8:1, preferably about 2.4:1.The sodium silicate is activated with from 50 to 2000 ppm alumina at atemperature of from 15° to 100° C. for at least 10 minutes, preferablywith from 400 to 600 ppm alumina at room temperature, most preferablywith about 500 pp alumina. The sodium silicate solution is heated to atemperature of between 80° and 120° C., preferably 90° C. The sodiumaluminate solution is also heated to a temperature of between 80° and120° C., preferably 90° C. The composition of the reaction mixture has asodium oxide to silica molar ratio of between 0.5 and 1.0:1, preferablyabout 0.56:1. It has a silica to alumina molar ratio of between 7:1 and30:1, preferably between 7:1 and 10:1, and most preferably of about7.8:1. The reaction mixture also has a water to sodium oxide molar ratioof between 10:1 and 90:1, preferably between 20:1 and 40:1 and mostpreferably of about 20:1. The reaction mixture is reacted at atemperature of from 80° to 120° C. until crystalline zeolite Y isformed, preferably at a temperature of from 80° to 100° C., mostpreferably at a temperature of about 100° C. The sodium silicate motherliquor may be recycled as a source of sodium silicate solution.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In its broadest aspect, the present invention is based upon fourdifferent discoveries: (1) the discovery that the type of zeolite formedis determined by how long it takes for the zeolite to be formed at agiven reaction temperature; (2) the discovery that the reaction timeneeded to crystallize a zeolite at a given reaction temperature is afunction primarily of the water to sodium oxide molar ratio, with thesodium oxide to silica and silica to alumina molar ratios having asmaller effect on reaction time; (3) the discovery that the magnesiumexchange capacity of zeolite A is a function of particle size of thezeolite; and (4) the discovery that the particle size of a zeolite is afunction of silica to alumina molar ratio, sodium oxide to alumina molarratio, and alumina concentration.

The zeolites of small and uniform particle size of this invention areproduced using these four discoveries in a reaction mixture having ahigh silica to alumina molar ratio, with the other oxide molar ratiosadjusted to produce the desired zeolite. In the known processes forforming zeolites, a reaction mixture of sodium-aluminum-silicate wateris prepared having a particular composition. This mixture is maintainedat a certain temperature until crystals are formed, then the crystalsare separated from the reaction mixture. For silica to alumina molarratios greater than two, the reaction mixture consists of a sodiumsilicate mother liquor and an amorphous sodium alumino silicate pigment.When this two phase reaction mixture is reacted at elevatedtemperatures, nothing visually happens for a certain period of time, butafter that period of time the zeolite rapidly crystallizes and can thenbe separated from the reaction mixture.

The present invention is based in part upon the discovery that, for anyparticular source of silica, the type of zeolite formed is determined bythe reaction time necessary for the beginning of crystallization tooccur at a given reaction temperature. When the reaction time is short,hydroxy-sodalite is formed, but when the reaction time is longer,zeolite A is formed. When the reaction time is still longer, zeolite Xis formed. When the reaction time is between that necessary for theformation of zeolite A and that necessary for the formation of zeoliteX, then a combination of zeolite A and zeolite X is formed. The reactiontime is dependent upon the source of silica and whether or not thesilica has been activated. The preferred reaction time can be foundreadily by experimentation for any particular source of silica.

The reaction time necessary for crystallization at a given reactiontemperature can be controlled in a variety of ways, but the major way ofcontrolling reaction time is by adjusting the water to sodium oxidemolar ratio of the reaction mixture. The reaction time necessary to forma zeolite is directly proportional to the water to sodium oxide molarratio used. For instance, when the source of silica is not activatedwith alumina, the preferred water to sodium oxide molar ratio for makingzeolite A is between 15:1 and 20:1; for making zeolite X, it is between30:1 and 60:1 and for making a combination of zeolite X and zeolite A itis between 25:1 and 35:1. One possible explanation is that a higherwater to sodium oxide ratio means the solution is more dilute, whichmeans that it takes longer for the reaction sites to come together,which causes a longer reaction time. Therefore, to get a zeolite A in areaction mixture having a sodium oxide to silica molar ratio and asilica to alumina molar ratio where normally a zeolite X would beformed, one would decrease the water to sodium oxide ratio. Adjustingthe water to sodium oxide molar ratio is the main control fordetermining which type of zeolite is formed and is analogous to a coursecontrol on a proportional feedback controller.

This relationship between the water to sodium oxide molar ratio and thetype of zeolite formed was not previously known. For instance, prior artU.S. Pat. Nos. 2,882,243 and 2,882,244, show a water to sodium oxidemolar ratio of from 35 to 200 for the production of zeolite A and awater to sodium oxide molar ratio of from 35 to 60 for the production ofzeolite X, respectively. If anything, this would imply that the reactionmixture for preparing zeolite A should have a higher water to sodiumoxide molar ratio than the reaction mixture for preparing zeolite X,which is not the case. In U.S. Pat. No. 3,119,659, the water to sodiumoxide molar ratio for the production of zeolite A is from 20 to 100while the water to sodium oxide molar ratio for the production ofzeolite X is from 30 to 60. None of the above patents show that thewater to sodium oxide molar ratio should be higher for making zeolite Xthan for making zeolite A.

Another way of controlling the reaction time necessary forcrystallization at a given reaction temperature is by adjusting thesodium oxide to silica molar ratio of the reaction mixture. The reactiontime necessary to form a zeolite is inversely proportional to the sodiumoxide to silica molar ratio used. The effect of sodium oxide to silicamolar ratio is less pronounced than that of water to sodium oxide molarratio.

One possible theory as to why increasing the sodium oxide to silicamolar ratio would decrease the reaction time necessary to form a zeoliteis that increasing the sodium oxide to silica molar ratio, for a givenwater to sodium oxide molar ratio reduces the viscosity of the reactionmixture.

Adjusting the silica to alumina molar ratio of the reaction mixture alsoaffects the reaction time necessary for crystallization at a givenreaction temperature, but this effect is much less than the effect ofsodium oxide to silica molar ratio, which in turn is much less than theeffect of water to sodium oxide molar ratio. For a given water to sodiumoxide molar ratio and a given sodium oxide to silica molar ratio, thereaction time necessary to form a zeolite is directly proportional tothe silica to alumina molar ratio.

The reaction time at a given temperature can be reduced by adding thesodium aluminate solution to the sodium silicate solution at a fast rateof addition, preferably so that all of the sodium aluminate solution isadded within 30 seconds, and more preferably simultaneously. Thus, thereaction time necessary for crystallization at a given reactiontemperature can be increased by increasing the water to sodium oxideratio; decreasing the sodium oxide to silica molar ratio; increasing thesilica to alumina molar ratio and adding the two materials at a slowrate of addition.

Using these criteria, it has been found that the preferred reaction timefor forming zeolite A is about 1/2 to 8 hours, for zeolite X, about 1/2to 8 hours, and mixtures of zeolites A and X, about 4 to 8 hours.

The present invention is also based upon the discovery that themagnesium exchange capacity of zeolite A is a function of zeoliteparticle size. As the particle size decreases, the magnesium exchangecapacity increases. For zeolite A, when the average diameter is 2.4microns, the magnesium capacity is only 62 mg/g, when the averagediameter is 1.1 microns, the magnesium capacity is about 124 mg/g, andwhen the average diameter is 0.8 microns, the magnesium capacity is 159mg/g.

Much more important than the effect of silica to alumina molar ratio onreaction time is the effect of silica to alumina molar ratio on particlesize. The reason for this effect is not known but the particle size of azeolite increases as the silica to alumina molar ratio of the reactionmixture decreases. The particle size decreases as the silica to aluminamolar ratio increases in the reaction mixture. For instance, the silicato alumina molar ratio of zeolite A is 1.85±0.5. Therefore, a zeolite Aformed in a reaction mixture having a silica to alumina molar ratio of10.1 would have a smaller particle size than a zeolite A formed in areaction mixture having a silica to alumina molar ratio of 2:1. Thismeans that one can control the particle size of a zeolite by adjustingthe silica to alumina molar ratio of the reaction mixture. In order toincrease particle size one would adjust the silica to alumina molarratio of the reaction mixture so that it approaches the silica toalumina molar ratio of the desired product. For zeolite A, that ratio is1.85±0.5. For zeolite X it is 2.5±0.5. In order to decrease particlesize one would adjust the silica to alumina molar ratio of the reactionmixture so that it departs from the silica to alumina molar ratio of thedesired product.

For zeolite A down to SiO₂ :Al₂ O₃ ratio of 2 or above, and for zeoliteX, the silica to alumina molar ratios of the reaction mixtures used inthe present invention are higher than the silica to alumina molar ratiosof the desired product. Therefore, to increase the particle size ofeither zeolite X or zeolite A or a combination thereof, one woulddecrease the silica to alumina molar ratio of the reaction mixture. Inorder to decrease the particle size, one would increase the silica toalumina molar ratio of the reaction mixture.

Other means of controlling the particle size of the final productinclude adjusting either the sodium oxide to alumina molar ratio or thealumina concentration of the reaction mixture. The particle size isinversely proportional to the sodium oxide to alumina molar ratio, anddirectly proportional to the alumina concentration. The effects of thesodium oxide to alumina molar ratio and the effects of aluminaconcentration on particle size are of similar magnitude as the effect ofsilica to alumina molar ratio.

Since silica to alumina molar ratio, sodium oxide to alumina molarratio, and alumina concentration are all interrelated, it is unclear, atpresent, which is the predominate factor, but any of the three variablesor a combination thereof can be used to control particle size.

The sodium oxide to silica molar ratio of the reaction mixture alsoaffects the particle size of the final product, but this effect is muchsmaller in magnitude than the effect of silica to alumina molar ratio.For a constant silica to alumina molar ratio, the particle size isinversely proportional to the sodium oxide to silica molar ratio. As thesodium oxide to silica molar ratio increases, the particle sizedecreases. As the sodium oxide to silica molar ratio decreases, theparticle size increases. Thus, the effect of sodium oxide to silicamolar ratio of the reaction mixture on particle size can be used incombination with the effect of silica to alumina molar ratio of thereaction mixture on particle size as a means of controlling particlesize.

The water to sodium oxide molar ratio of the reaction mixture alsoaffects the particle size of the final product, but this effect issmaller in magnitude than the effect of sodium oxide to silica molarratio. The reaction temperature also affects the particle size.

Although batch composition and reaction temperature are used to controlparticle size, there are conditions under which agglomeration can occur.Agglomeration will result in a product which does not exhibit theexpected particle size or properties. The processes as described in thepatent examples are directed to optimum conditions under which there isno agglomeration. If the temperature of the reactants at the time ofmixing is too low or the concentration of the sodium oxide or water areseverely altered in the solutions being used, one can expectagglomeration. At an extreme a bimodal distribution may appear. Theseeffects can be overcome by such techniques as longer rates of addition,reverse sequence of addition, higher agitation speeds, etc. The point isthat these techniques are not really controlling the primary particlesize, they are merely changing the degree of agglomeration. Only batchcomposition and reaction temperature control primary particle size, andthe type of the product formed.

In the present invention, the zeolites of small and uniform size havinghigh magnesium exchange capacities are produced by forming a sodiumaluminate solution, forming a sodium silicate solution, and mixing thesodium aluminate solution and the sodium silicate solution to produce areaction mixture. For SiO₂ :Al₂ O₃ molar ratios greater than 2, thismixture comprises a sodium silicate mother liquor and an amorphoussodium alumino silicate pigment. For such ratios of 2 or below, themixture contains a sodium aluminate mother liquor. The reaction mixtureis heated and reacted at a temperature of from 40° to 120° C.,preferably 60° to 100° C. until the desired zeolite is formed, andrecovering the desired zeolite from the mother liquor. In the preferredprocedure, the sodium silicate and sodium silicate solution arepreheated to a temperature of 50° to 120° C., preferably 60° to 100° C.,prior to mixing. After mixing an exothermic reaction occupy which raisesthe temperature about 10° C. at which temperature the reaction takesplace. The zeolite is then recovered from the reaction mixture byconventional solids separation techniques such as filtration. The motherliquor or filtrate may be recycled to provide dissolved values of sodiumand silica or sodium and alumina.

In one aspect, the sodium silicate solution used in this process can beformed by dissolving sand in a sodium hydroxide solution at a pressureof at least 100 psig and a temperature of at least 130° C. to produce asodium silicate solution having a silica to sodium oxide molar ratio ofbetween 2.4:1 and 2.8:1. The word "sand" is to be given its usualmeaning of "a loose material consisting of small but easilydistinguishable grains, usually less than two millimeters in diameter,most commonly of quartz resulting from the disintegration of rocks, andcommonly used for making mortar and glass, as an abrasive, or for moldsin founding." A temperature of at least 130° C. is used to dissolve thesand because it is more difficult to dissolve sand at lowertemperatures.

This sodium silicate solution is activated with from 50 to 2000 ppmalumina preferably, and heated to a temperature between 40° and 120° C.for at least 10 minutes, preferably with 400 to 600 ppm alumina at roomtemperature. Alumina concentrations of less than 50 ppm alumina do notactivate the silica. Alumina concentrations of more than 2000 ppm causethe alumina to precipitate out of the solution as an amorphous sodiumalumino silicate. Preferably the silica to sodium oxide molar ratio ofthe sodium silicate solution is about 2.4:1 to 2.8:1, since this sodiumsilicate solution is usually less expensive to make than solutionshaving higher silica to sodium oxide molar ratios, such as waterglass.Activation of the sodium silicate solution is necessary in theproduction of zeolite Y but optional in production of zeolites A and X,and mixtures of A and X.

After a sodium silicate solution is formed, and is either activated ornot activated, a sodium aluminate solution is mixed with the sodiumsilicate solution as by addition to form a reaction mixture.

When the sodium silicate source has been activated with alumina, thepreferred reaction mixture for zeolite A formation has a water to sodiumoxide molar ratio of between 25:1 and 35:1; a sodium oxide to silicamolar ratio of between 1.4:1 and 2:1; and a silica to alumina molarratio of between 3:1 and 7:1. When the sodium silicate source has notbeen activated with alumina, the preferred reaction mixture has a waterto sodium oxide molar ratio of between 15:1 and 20:1; a sodium oxide tosilica molar ratio of between 1.5:1 and 2:1; and a silica to aluminamolar ratio of between 2:1 and 4:1.

When the sodium silicate source has been activated with alumina, thepreferred reaction mixture for zeolite X formation has a water to sodiumoxide molar ratio of between 30:1 and 40:1; a sodium oxide to silicamolar ratio of between 1:1 and 1.2:1 and a silica to alumina molar ratioof between 5:1 and 7:1. When the sodium silicate source has not beenactivated with alumina, the preferred reaction mixture has a water tosodium oxide molar ratio of between 30:1 and 60:1; a sodium oxide tosilica molar ratio of between 1.2:1 and 1.7:1 and a silica to aluminamolar ratio of between 6:1 and 8:1.

When the sodium silicate source has been activated with alumina, thepreferred reaction mixture for forming a mixture of zeolites A and X hasa water to sodium oxide mola ratio of between 15:1 and 60:1; a sodiumoxide to silica molar ratio of between 0.7:1 and 1.7:1; and a silica toalumina molar ratio of between 5:1 and 10:1. When the sodium silicatesource has not been activated with alumina, the preferred reaction has awater to sodium oxide molar ratio of between 20:1 and 50:1; a sodiumoxide to silica molar ratio of between 1.4:1 and 3:1; and a silica toalumina molar ratio of between 2:1 and 10:1.

As the water to sodium oxide molar ratio falls below 10:1, for thesodium oxide to silica and silica to alumina molar ratios of the presentinvention, there is an increased probability of forming zeolite Ainstead of a combination of zeolite A and zeolite X. As the water tosodium oxide molar ratio approaches 60:1, for the sodium oxide to silicaand silica to alumina molar ratios of the present invention, there is anincreased probability of forming zeolite X instead of a combination ofzeolite A and zeolite X.

Zeolite Y can be formed from a sodium silicate source activated withalumina when the reaction mixture has a sodium oxide to silica molarratio of between 0.5:1 and 1:1; and a silica to alumina molar ratio ofbetween 7:1 and 30:1. The preferred reaction mixture has a sodium oxideto silica molar ratio of between 0.5:1 and 1:1; and a silica to aluminamolar ratio of between 7:1 and 10:1.

The broad oxide mole ratio ranges for making each zeolite are shown inTable I.

                  TABLE I                                                         ______________________________________                                        BROAD RANGES FOR MAKING ZEOLITES                                                      Water/       Sodium Oxide/                                                                             Silica/                                      Zeolite Sodium Oxide Silica      Alumina                                      ______________________________________                                        A       10-35          1-4       1-10                                         X       25-90          1-3       5-10                                         X & A   10-60        0.5-3       2-15                                         Y       10-90        0.5-1       7-30                                         ______________________________________                                    

The preferred oxide mole ratio ranges for making each zeolite using asource of sodium silicate that has not been activated with alumina areshown in Table II.

                  TABLE II                                                        ______________________________________                                        PREFERRED RANGES FOR MAKING ZEOLITES                                          (Unactivated)                                                                         Water/       Sodium Oxide/                                                                             Silica/                                      Zeolite Sodium Oxide Silica      Alumina                                      ______________________________________                                        A       15-20        1.4-2       2-4                                          X       30-60          1.2-1.7   6-8                                          X & A   20-50        1.6-3        2-10                                        ______________________________________                                    

The preferred oxide mole ratio ranges for making each zeolite using asource of sodium silicate that has been activated with alumina are shownin Table III.

                  TABLE III                                                       ______________________________________                                        PREFERRED RANGES FOR MAKING ZEOLITES                                          (Activated)                                                                           Water/       Sodium Oxide/                                                                             Silica/                                      Zeolite Sodium Oxide Silica      Alumina                                      ______________________________________                                        A       25-35        1.4-2       3-7                                          X       30-40          1-1.2     5-7                                          X & A   15-60          0.7-1.7   5-10                                         Y       20-40        0.5-1       7-10                                         ______________________________________                                    

To ensure a good yield of the desired zeolite product, it is necessaryto react the zeolite mixture beyond a certain minimum time. If, however,the reaction is continued too long, the product starts to lose silica,that is the silica to alumina ratio starts to fall, and if the reactionis continued even further, then the product may recrystallize to anundesirable zeolitic material. There is an optimum reaction time whichis, in part, determined by the ratios and concentrations of the originalreaction mixture, by the size of the batch, the time required to mix theingredients and the rate of heating. The optimum reaction time forparticular molar ratios can readily be determined by experiment.However, in general reaction times for zeolite A production range from0.5 to 8 hours, and for zeolite X from 2 to 8 hours.

Once the zeolite has been separated from the mother liquor, the motherliquor may be recycled. Recycling of the mother liquor eliminates theproblem of how to dispose of the mother liquor. Although it is possibleto use the process of the present invention without recycling the motherliquor, failure to recycle the mother liquor could make the process costprohibitive.

The silica to alumina molar ratio of zeolite X is about 2.5:1 and thesilica to alumina molar ratio of zeolite A is about 1.85:1. As statedabove, the particle size of the zeolite is smaller when the silica toalumina molar ratio of the reaction mixture is higher than the silica toalumina molar ratio of the desired zeolite, at silica to alumina molarratios of greater than 2. Because of this, the zeolite X and the zeoliteA of the present invention have smaller particle sizes than those of theprior art.

Because of their small particle size, the zeolite X, the zeolite A andmixtures of the present invention are both useful in a variety of usessuch as an ion-exchange material in water softening compositions anddetergents; as a filler in paper, rubber and plastics; and as anon-settling flatting pigment. Zeolite Y is useful as an adsorbent.

The zeolite A, having a smaller particle size, has a higher magnesiumion exchange capacity than prior art zeolite A having larger particlesizes. This increased magnesium ion exchange capacity makes this zeoliteA expecially useful as an ion exchange material in water softeningcompositions and detergents.

Another factor that makes the zeolites especially useful as ion exchangematerials is their fast calcium carbonate depletion rate. These zeolitesremove calcium ions faster than zeolites having larger particle sizes.The zeolite A having the smaller particle size exchanges the calciumions at a faster rate than the zeolite A having the larger particlesize.

As can be seen in Tables I, II and III, the ranges of water to sodiumoxide molar ratios needed to produce zeolite X, zeolite A, a combinationof zeolite X and zeolite A or zeolite Y overlap each other. The water tosodium oxide molar ratio is the major controlling factor whichdetermines the reaction time necessary for crystallization at a givenreaction temperature, which in turn determines the type of zeoliteformed. But, as stated above, there are other factors that have asmaller effect on reaction time, such as sodium oxide to silica molarratio, silica to alumina molar ratio, degree of agitation and rate ofaddition of the sodium aluminate solution to the sodium silicatesolution. These additional factors can either add to or subtract fromthe effect of water to sodium oxide molar ratio.

For instance, either zeolite X or zeolite A can be formed from areaction mixture having a water to sodium oxide molar ratio of 30:1. Inthat case, the additional factors would determine which type of zeolitewould be produced. If the sodium oxide to silica molar ratio is 1.2:1and the silica to alumina molar ratio is 8:1, then zeolite X will beproduced. But if the sodium oxide to silica molar ratio is 2:1 and thesilica to alumina molar ratio is 3:1, then zeolite A will be produced.The type of zeolite formed depends on the total effect of the water tosodium oxide molar ratio and all of the additional factors mentionedabove.

One of the results of using the principles of the present invention isthe ability to make a controlled combination of zeolite X and zeolite Ain the same reaction. A combination of from 20 to 80% zeolite X and from20 to 80% zeolite A can be formed by adjusting the reaction timenecessary for crystallization to a time between that required to makezeolite X and that required to make zeolite A. The composition of thecombination depends on the reaction time. If the reaction time is closeto that required to make zeolite X, much more zeolite X will be formedthan zeolite A. If, on the other hand, the reaction time is close tothat of zeolite A, much more zeolite A will be formed than zeolite X. Byadjusting the reaction time, one can make any desired combination ofzeolite X and zeolite A.

The combination of zeolite X and zeolite A has an average particle sizeless than 2 microns in diameter. It is useful, because of its smallparticle size, as an ion exchange material in water softeningcompositions and detergents, as a filler in paper, rubber and plastics,and as a non-settling flatting pigment.

Any source of sodium silicate can be used in the present invention, butone particularly desirable source of sodium silicate is sand dissolvedin caustic. The advantage of this source is its low cost. The sand isdissolved in a sodium hydroxide solution at a pressure of at least 100psig and a temperature of at least 130° C. to produce a sodium silicatesolution having a silica to sodium oxide molar ratio of between 2.4:1and 2.8:1. Preferably the pressure is about 140 psig, producing a sodiumsilicate solution having a silica to sodium oxide molar ratio of about2.4:1. Activation of the silica is always used in production of zeoliteY.

The time required to produce a given product from batches of identicalchemical composition will be dependent on the source of silicon dioxide.Each different type of silica source has its own time table specifyingthe reaction times needed to form each type of zeolite. One of thediscoveries upon which this invention is based is the fact that thistime table can be changed by activating the silica source with alumina,as described above. The alumina concentration limits of 50 to 2000 ppmalumina are critical values since alumina concentrations below 50 ppmfail to activate the sodium silicate solution.

The alumina used to activate the sodium silicate solution may suitablybe provided by a soluble aluminum compound such as sodium aluminate or awater soluble aluminum salt, such as aluminum sulphate. Sodium aluminateis, however, the preferred reagent since it limits the tendency tointroduce foreign ions into the zeolite lattice.

There is an important difference between the effect of activation andthe effect of reaction time controlling factors such as water to sodiumoxide molar ratio, sodium oxide to silica molar ratio, silica to aluminamolar ratio and rate of addition. The reaction time controlling factorsare used to adjust the reaction time necessary for crystallization sothat it will match with the reaction time in a time table produce aparticular zeolite. Activation changes the time table. For that reason,the preferred oxide mole ratios for producing a desired zeolite aredifferent when a source of silica is either activated or not activated(see Tables II and III above).

ln accordance with a main embodiment of the present invention, it hasbeen found that zeolite products of small and uniform size and with anarrow differential weight percent distribution, are formed by properselection of the molar ratios and temperatures under which the zeolitesare produced. The selection of molar ratios and temperature are from theranges of molar ratios and temperatures for conducting the reaction setforth above. It has been found that if selections of the molar ratios inthe reacting batch together with the temperature range, are inaccordance with the following equation that small particle size zeolitesof uniform and predictable size and properties or characteristics willresult. This equation is as follows where ln is natural log:

    ______________________________________                                        Average ln =                                                                               A(N/S × S/A) + B(H/N ×                               (Particle Size)                                                                           Temp/100) + C(S/A).sup.3 + D(S/A).sup.2 +                                     E(H/N ÷ S/A) + F(S/A) + G(Temp/100).sup.3 +                               H(H/N ÷ N/S) + I(N/S).sup.2 +                                             J(N/S ÷ S/A) + K                                              ______________________________________                                    

wherein average particle size is expressed in microns.

H/N--Moles of H₂ O÷moles Na₂ O present in the batch;

N/S--Moles Na₂ O÷moles SiO₂ present in the batch;

S/A--Moles SiO₂ O÷moles Al₂ O₃ present in the batch;

Temp--Reaction temperature in degrees Celsius at which the batch is helduntil crystallization is complete;

and A, B, C, D, E, F, G, H, I, J and K are constants having thefollowing values:

    ______________________________________                                                   A = -0.14827                                                                  B =  0.11922                                                                  C = -0.03245                                                                  D =  0.59054                                                                  E = -0.10945                                                                  F = -3.31907                                                                  G = -0.50955                                                                  H =  0.00532                                                                  I =  0.12626                                                                  J = -0.76339                                                                  K =  5.40831                                                       ______________________________________                                    

Selection of the batch molar ratios and temperature in accordance withthe above equation enables one to produce zeolites of the desiredaverage particle size. Further, if the molar ratios and temperature areselected from the ranges described in this invention, the resultingaverage particle size will be within the limits set forth herein. Thus,use of this equation or formula enables one to produce zeolite productswherein 90% of the particles are less than two microns in diameter andwherein the average particle size is no more than about 1.6 microns.

It will be understood that the equation set forth herein enables one toaccurately predict the average particle size produced as a result of thereaction. To predict the particle size, the appropriate molar ratio andtemperature are selected from within the ranges provided herein and thevalues are inserted into the equation. The resulting particle size ofthe zeolite is then predictable from the values employed for the variousmolar ratios and temperature.

This is an unexpected advance in the art in the production of zeolitesin that the prior art heretofore has not been able to consistentlyproduce zeolite particles of small and uniform size and of thisuniformity of particle size. The prior art indicates that a smallportion of small particle size zeolites is produced together with apredominance of larger particle size zeolites but there is no prior artof which applicant is aware which enables one to produce uniform smallparticle size modified zeolites.

Because of the small particle size, the zeolites of the presentinvention are useful in a variety of area such as ion-exchange materialsin water softening compositions and detergents; as fillers in paper,rubber and plastics; and as non-settling flatting pigments. Thiszeolite, having a smaller particle size, has a higher magnesium ionexchange capacity than zeolite A having larger particle sizes. Thisincreased magnesium ion exchange capacity makes the zeolite especiallyuseful as an ion exchange material in water softening compositions anddetergents. Another factor that makes the zeolite especially useful asan ion exchange material is its fast calcium carbonate depletion rate.These zeolites remove calcium ions faster than zeolites having largerparticle sizes.

The zeolites of the present invention are also advantageous overconventional zeolites such as zeolite A because of their increased portsize, i.e. increased pore diameter over conventional zeolite A. Aspointed out above, the concept of increased pore diameter in the smallparticle size zeolites of the present invention is supported by surfacearea measurements. These surface area measurements are set forthhereinafter. In general, however, these surface area measurementsindicate that the surface areas of the modified zeolites of the presentinvention are greater than about 10 m² /g and preferably in the range ofabout 10 m² /g to 170 m² /g.

EXAMPLES

The invention will be further illustrated by the following exampleswhich set forth particularly advantageous method and compositionembodiments. While the examples illustrate the present invention, theyare not intended to limit it. In the examples and throughout thedisclosure, parts are by weight unless otherwise indicated.

The following examples were carried out as described herein by formingthe silicate and aluminate solutions, preheating each solution to theindicated temperature, and adding the aluminate solution to the silicatesolution in the time specified. The resulting gel was broken down byagitation until a homogeneous slurry was obtained and the batch was thenreacted at the indicated temperature for the reaction period. Theresulting product was characterized by its calcium ion exchange capacitybased on mg calcium carbonate/g zeolite, and magnesium ion exchangecapacity based on mg magnesium carbonate/g zeolite. The resultingzeolite particles are characterized by differential weight percentgaussian distribution with an average particle size in microns and anindication of the weight between 0.1 and 2.5 microns. The cumulativepercent population is also described. These criteria are set forth inthe following tables.

In the examples, calcium carbonate exchange capacity was determined byplacing the zeolite in an exchange solution, agitating for fifteenminutes, filtering off the zeolite and titrating the filtrate with EDTA(ethylenediaminetetraacetic acid) solution to determine how much calciumions had been removed. The exchange solution was made from calciumchloride to obtain a concentration equivalent to 122 g calcium carbonateper liter. The filtrate was buffered to pH 10, then Erichrome Black Tindicator(3-hydroxy-4-((1-hydroxy-2-naphthyl)azo)-7-nitrol-naphthalenesulfonicacid sodium salt) was added to the filtrate prior to EDTA titration.

Magnesium carbonate exchange capacity was determined by placing thezeolite in an exchange solution, agitating for fifteen minutes,filtering off the zeolite and titrating the filtrate with EDTA solutionto determine how much magnesium ions have been removed. The exchangesolution was made from magnesium chloride to obtain a concentrationequivalent to 1000 ppm magnesium carbonate. The filtrate was buffered topH 10, then Erichrome Black T indicator was added to the filtrate priorto EDTA filtration.

Particle size measurements were made by Coulter Counter (Model TAII).Particle size analysis by Coulter Counter measures both sample volumeand number of particles in specific size ranges. Since volume % andweight % are synonymous when all particles have the same density, weight% is used since it is the most conventional way to express particle sizedata.

The following terms have been used in describing the particle size ofthe present invention:

Gaussian distribution: The frequency curves of a gaussian distribution,also known as symmetrical or bell-shaped frequency curves, arecharacterized by the fact that observations equidistant from the centralmaximum have the same frequency.

Average particle size: The average particle size is the size at which50% of the total weight is accounted for. Results were confirmed byScanning Electron Microscope.

Cumulative % population: The cumulative % population is the percentageof all the counted particles.

The following are examples for preparation of zeolites simiIar tozeolite A and characterization of the products. In these examples, theexchange rates refer to the zeolite on an anhydrous basis.

                  TABLE IV                                                        ______________________________________                                        COMPOSITION OF REACTION MIXTURE                                               FOR THE PREPARATION OF ZEOLITE A                                              Ex-  Water/  Sodium  Silica/     %                                            am-  Sodium  Oxide/  Alu-  %     Sodium                                                                              %     % Alu-                           ple  Oxide   Silica  mina  Water Oxide Silica                                                                              mina                             ______________________________________                                        1    30      3.0     2.5   95.34 3.18  1.06  0.42                             2    25      2.4     3.0   94.14 3.77  1.57  0.52                             3    25      2.4     3.0   94.14 3.77  1.57  0.52                             4    25      2.4     2.5   94.04 3.76  1.57  0.63                             5    25      2.4     2.0   93.90 3.76  1.57  0.78                             6    25      2.4     2.0   93.90 3.76  1.57  0.78                             7    25      2.0     2.5   93.63 3.75  1.87  0.75                             8    25      2.0     2.0   93.46 3.74  1.87  0.93                             9    25      2.0     2.0   93.46 3.74  1.87  0.93                             10   20      3.0     2.5   93.17 4.66  1.55  0.62                             11   20      3.0     2.5   93.17 4.66  1.55  0.62                             12   20      3.0     2.5   93.17 4.66  1.55  0.62                             13   20      2.8     2.5   93.02 4.65  1.66  0.66                             14   20      2.8     2.5   93.02 4.65  1.66  0.66                             15   20      2.8     2.5   93.02 4.65  1.66  0.66                             16   20      2.6     2.5   92.86 4.64  1.79  0.71                             17   20      2.6     2.5   92.86 4.64  1.79  0.71                             18   20      2.6     2.5   92.86 4.64  1.79  0.71                             19   20      2.2     5.3   92.85 4.64  2.11  0.40                             20   25      1.6     2.0   92.81 3.71  2.32  1.16                             21   20      2.4     3.0   92.78 4.64  1.93  0.65                             22   20      2.4     3.0   92.78 4.64  1.93  0.65                             23   20      2.2     4.3   92.76 4.64  2.11  0.49                             24   20      2.0     7.3   92.73 4.64  2.32  0.32                             25   20      2.0     7.3   92.73 4.64  2.32  0.32                             26   20      2.0     6.3   92.68 4.63  2.32  0.37                             27   20      2.4     2.5   92.66 4.63  1.93  0.77                             28   20      2.4     2.5   92.66 4.63  1.93  0.77                             29   20      2.4     2.5   92.66 4.63  1.93  0.77                             30   20      2.4     2.5   92.66 4.63  1.93  0.77                             31   20      2.0     5.3   92.62 4.63  2.32  0.44                             32   20      1.9     7.3   92.60 4.63  2.44  0.33                             33   20      2.0     4.3   92.52 4.63  2.31  0.54                             34   20      2.4     2.0   92.49 4.62  1.93  0.96                             35   20      2.4     2.0   92.49 4.62  1.93  0.96                             36   20      1.8     7.3   92.46 4.62  2.57  0.35                             37   20      2.2     2.5   92.44 4.62  2.10  0.84                             38   20      2.2     2.5   92.44 4.62  2.10  0.84                             39   20      2.2     2.5   92.44 4.62  2.10  0.84                             40   20      1.8     6.3   92.41 4.62  2.57  0.41                             41   20      2.0     3.3   92.37 4.62  2.31  0.70                             42   20      2.0     3.3   92.37 4.62  2.31  0.70                             43   20      1.7     7.3   92.30 4.62  2.72  0.37                             44   20      1.8     4.3   92.23 4.61  2.56  0.60                             45   20      2.0     2.5   92.17 4.61  2.30  0.92                             46   20      2.0     2.5   92.17 4.61  2.30  0.92                             47   20      2.0     2.5   92.17 4.61  2.30  0.92                             48   20      2.0     2.5   92.17 4.61  2.30  0.92                             49   20      1.6     7.3   92.12 4.61  2.88  0.39                             50   20      1.6     7.3   92.12 4.61  2.88  0.39                             51   20      1.6     7.3   92.12 4.61  2.88  0.39                             52   20      1.6     7.3   92.12 4.61  2.88  0.39                             53   20      1.6     7.3   92.12 4.61  2.88  0.39                             54   20      1.8     3.3   92.06 4.60  2.56  0.77                             55   20      1.6     5.3   91.98 4.60  2.87  0.54                             56   20      2.0     2.0   91.95 4.60  2.30  1.15                             57   20      2.0     2.0   91.95 4.60  2.30  1.15                             58   20      1.5     7.3   91.92 4.60  3.06  0.42                             59   20      1.5     7.3   91.92 4.60  3.06  0.42                             60   20      1.5     6.3   91.86 4.59  3.06  0.49                             61   20      1.5     6.3   91.86 4.59  3.06  0.49                             62   20      1.8     2.5   91.84 4.59  2.55  1.02                             63   20      1.8     2.5   91.84 4.59  2.55  1.02                             64   20      1.8     2.5   91.84 4.59  2.55  1.02                             65   20      1.5     5.3   91.77 4.59  3.06  0.58                             66   20      1.4     7.3   91.69 4.59  3.28  0.45                             67   20      1.6     3.3   91.68 4.58  2.87  0.87                             68   20      1.6     3.3   91.68 4.58  2.87  0.87                             69   20      1.6     3.3   91.68 4.58  2.87  0.87                             70   20      1.6     3.3   91.68 4.58  2.87  0.87                             71   20      1.6     3.3   91.68 4.58  2.87  0.87                             72   20      1.4     6.3   91.63 4.58  3.27  0.52                             73   20      1.6     3.0   91.60 4.58  2.86  0.96                             74   20      1.4     5.3   91.54 4.58  3.27  0.62                             75   20      1.6     2.5   91.43 4.57  2.86  1.14                             76   20      1.6     2.5   91.43 4.57  2.86  1.14                             77   20      1.4     3.3   91.20 4.56  3.26  0.99                             78   20      1.6     2.0   91.17 4.56  2.85  1.42                             79   20      1.6     2.0   91.17 4.56  2.85  1.42                             80   20      1.2     7.3   91.13 5.56  3.80  0.52                             81   20      1.2     6.3   91.05 4.55  3.79  0.60                             82   20      1.4     2.5   90.91 4.55  3.25  1.30                             83   20      1.4     2.5   90.91 4.55  3.25  1.30                             84   20      1.2     4.3   90.80 4.54  3.78  0.88                             85   20      1.2     3.3   90.56 4.53  3.77  1.14                             86   15      2.4     2.5   90.45 6.03  2.51  1.01                             87   15      2.4     2.0   90.23 6.02  2.51  1.25                             88   20      1.2     2.5   90.23 4.51  3.76  1.50                             89   15      2.0     2.0   89.55 5.97  2.99  1.49                             90   15      1.6     2.5   88.89 5.93  3.70  1.48                             91   15      1.6     2.0   88.56 5.90  3.69  1.85                             92   15      1.6     2.0   88.56 5.90  3.69  1.85                             ______________________________________                                    

                  TABLE V                                                         ______________________________________                                        ZEOLITE A - REACTION CONDITIONS                                               Ex-                            Reaction                                                                             Reaction                                am-  Temps. °C.                                                                           Time of     Temp.  Time                                    ple  Silicate                                                                              Aluminate Addition (sec.)                                                                         °C.                                                                           (Hrs.)                                ______________________________________                                        1    90      90        30        100    4.0                                   2    50      50        30        60     8.0                                   3    70      70        30        80     2.0                                   4    50      50        30        60     7.5                                   5    50      50        30        60     6.0                                   6    70      70        30        80     2.5                                   7    50      50        30        60     6.5                                   8    50      50        30        60     6.5                                   9    70      70        30        80     2.5                                   10   50      50        30        60     4.0                                   11   70      70        30        80     1.5                                   12   90      90        30        100    0.5                                   13   50      50        30        60     4.0                                   14   70      70        30        80     2.0                                   15   90      90        30        100    0.5                                   16   50      50        30        60     3.0                                   17   70      70        30        80     2.0                                   18   90      90        30        100    0.5                                   19   90      90        30        100    0.5                                   20   50      50        30        60     8.0                                   21   50      50        30        60     3.5                                   22   70      70        30        80     2.0                                   23   90      90        30        100    1.0                                   24   90      90        30        100    2.0                                   25   90      90        30        100    1.0                                   26   90      90        30        100    1.0                                   27   50      50        30        60     4.0                                   28   70      70        30        80     1.5                                   29   90      90        30        100    2.5                                   30   90      90        30        100    0.5                                   31   90      90        30        100    1.0                                   32   90      90        30        100    1.0                                   33   90      90        30        100    1.0                                   34   50      50        30        60     3.5                                   35   70      70        30        80     1.0                                   36   90      90        30        100    1.0                                   37   70      70        30        80     1.5                                   38   50      50        30        60     4.0                                   39   90      90        30        100    0.5                                   40   90      90        30        100    2.0                                   41   90      90        30        100    2.0                                   42   90      90        600       100    2.0                                   43   90      90        30        100    1.0                                   44   90      90        30        100    2.0                                   45   50      50        30        60     4.0                                   46   70      70        30        80     3.0                                   47   50      50        30        60     3.5                                   48   90      90        30        100    0.5                                   49   90      90        30        100    2.0                                   50   90      90        300       100    1.5                                   51   90      90        600       100    2.0                                   52   90      90        1200      100    2.0                                   53   90      90        30        100    2.0                                   54   90      90        30        100    1.0                                   55   90      90        30        100    2.0                                   56   50      50        30        60     4.5                                   57   70      70        30        80     1.5                                   58   90      90        30        100    2.0                                   59   90      90        30        100    2.0                                   60   90      90        30        100    8.0                                   61   90      90        30        100    2.0                                   62   70      70        30        80     1.5                                   63   50      50        30        60     4.0                                   64   90      90        30        100    0.5                                   65   90      90        30        100    2.0                                   66   90      90        30        100    4.0                                   67   90      90        30        100    1.5                                   68   90      90        30        100    1.5                                   69   90      90        300       100    1.5                                   70   90      90        600       100    1.5                                   71   90      90        1200      100    1.5                                   72   90      90        30        100    3.0                                   73   70      70        30        80     3.0                                   74   90      90        30        100    3.0                                   75   70      70        30        80     3.0                                   76   90      90        30        100    1.0                                   77   90      90        30        100    1.0                                   78   50      50        30        60     4.0                                   79   70      70        30        80     2.3                                   80   90      90        30        100    3.0                                   81   90      90        30        100    3.0                                   82   70      70        30        80     3.0                                   83   90      90        30        100    2.0                                   84   90      90        30        100    2.0                                   85   90      90        30        100    2.0                                   86   50      50        30        60     3.5                                   87   50      50        30        60     3.5                                   88   70      70        30        80     3.0                                   89   50      50        30        60     2.0                                   90   70      70        30        80     1.0                                   91   50      50        30        60     3.5                                   92   70      70        30        80     1.0                                   ______________________________________                                    

                                      TABLE VI                                    __________________________________________________________________________    EXCHANGE CAPACITY FOR ZEOLITE A                                                         Sodium                                                                   Silica/                                                                            Oxide/     Average                                                                            Calcium                                                                            Magnesium                                      Example                                                                            Alumina                                                                            Alumina                                                                            % Alumina                                                                           Diameter                                                                           Capacity                                                                           Capacity                                       __________________________________________________________________________    1    2.5  7.5  0.42  2.4  292   62                                            2    3.0  7.2  0.52  0.9  300  134                                            3    3.0  7.2  0.52  1.25 274  136                                            4    2.5  6.0  0.63  0.86 283  145                                            5    2.0  4.8  0.78  1.4  300  141                                            6    2.0  4.8  0.78  2.1  273  124                                            7    2.5  5.0  0.75  1.1  322  133                                            8    2.0  4.0  0.93  1.5  304  136                                            9    2.0  4.0  0.93  2.4  278  105                                            10   2.5  7.5  0.62  0.90 295  162                                            11   2.5  7.5  0.62  1.3  293  163                                            12   2.5  7.5  0.62  1.4  295  107                                            13   2.5  7.0  0.66  0.93 291  158                                            14   2.5  7.0  0.66  1.2  293  156                                            15   2.5  7.0  0.66  1.5  287  117                                            16   2.5  6.5  0.71  0.90 288  154                                            17   2.5  6.5  0.71  1.4  300  154                                            18   2.5  6.5  0.71  1.5  278  118                                            19   5.3  11.7 0.40  0.7  270  163                                            20   2.0  3.2  1.16  2.0  283  127                                            21   3.0  7.2  0.65  1.1  280  137                                            22   3.0  7.2  0.65  0.83 335  131                                            23   4.3  9.5  0.49  0.84 249  159                                            24   7.3  14.6 0.32  0.95 273  148                                            25   7.3  14.6 0.32  1.0  262  147                                            26   6.3  12.6 0.37  0.7  252  147                                            27   2.5  6.0  0.77  0.80 282  153                                            28   2.5  6.0  0.77  1.3  295  150                                            29   2.5  6.0  0.77  1.0  299  145                                            30   2.5  6.0  0.77  1.5  284  123                                            31   5.3  10.6 0.44  0.75 249  145                                            32   7.3  13.9 0.33  0.86 260  149                                            33   4.3  8.6  0.54  0.93 290  142                                            34   2.0  4.8  0.96  1.1  327  155                                            35   2.0  4.8  0.96  1.7  293  125                                            36   7.3  13.1 0.35  0.88 261  146                                            37   2.5  5.5  0.84  1.4  289  152                                            38   2.5  5.5  0.84  0.85 285  149                                            39   2.5  5.5  0.84  1.7  300  109                                            40   6.3  11.3 0.41  0.95 297  123                                            41   3.3  6.6  0.70  0.94 292  136                                            42   3.3  6.6  0.70  1.1  251  126                                            43   7.3  12.4 0.37  0.80 264  147                                            44   4.3  7.7  0.60  1.90 286   99                                            45   2.5  5.0  0.92  1.1  281  157                                            46   2.5  5.0  0.92  1.3  290  149                                            47   2.5  5.0  0.92  0.87 296  134                                            48   2.5  5.0  0.92  1.7  283  124                                            49   7.3  11.7 0.39  1.0  255  135                                            50   7.3  11.7 0.39  1.0  245  144                                            51   7.3  11.7 0.39  0.90 259  149                                            52   7.3  11.7 0.39  0.84 257  151                                            53   7.3  11.7 0.39  1.1  272  144                                            54   3.3  5.9  0.77  1.1  290  103                                            55   5.3  8.5  0.54  0.92 255  150                                            56   2.0  4.0  1.15  1.3  297  140                                            57   2.0  4.0  1.15  2.0  293  115                                            58   7.3  11.0 0.42  0.9  256  145                                            59   7.3  11.0 0.42  1.1  249  127                                            60   6.3  9.5  0.49  0.95 273  127                                            61   6.3  9.5  0.49  1.1  234  123                                            62   2.5  4.5  1.02  1.2  287  157                                            63   2.5  4.5  1.02  1.0  281  149                                            64   2.5  4.5  1.02  1.7  281  113                                            65   5.3  8.0  0.58  1.1  250  118                                            66   7.3  10.2 0.45  1.5  254  143                                            67   3.3  5.3  0.87  1.2  265  145                                            68   3.3  5.3  0.87  1.5  248  136                                            69   3.3  5.3  0.87  1.4  264  128                                            70   3.3  5.3  0.87  1.4  254  127                                            71   3.3  5.3  0.87  1.7  239   92                                            72   6.3  8.8  0.52  1.6  307  145                                            73   3.0  4.8  0.96  1.95 292  135                                            74   5.3  7.4  0.62  1.4  278  148                                            75   2.5  4.0  1.14  1.2  288  160                                            76   2.5  4.0  1.14  2.0  278   86                                            77   3.3  4.6  0.99  1.3  272  121                                            78   2.0  3.2  1.42  1.2  311  118                                            79   2.0  3.2  1.42  2.2  300  119                                            80   7.3  8.8  0.52  1.6  241  144                                            81   6.3  7.6  0.60  1.4  300  144                                            82   2.5  3.5  1.30  1.3  286  145                                            83   2.5  3.5  1.30  1.9  288  112                                            84   4.3  5.2  0.88  1.2  290  148                                            85   3.3  4.0  1.14  1.6  274  153                                            86   2.5  6.0  1.01  0.92 315  157                                            87   2.0  4.8  1.25  1.4  289  140                                            88   2.5  3.0  1.50  1.6  273  134                                            89   2.0  4.0  1.49  0.97 275  145                                            90   2.5  4.0  1.48  1.2  274  129                                            91   1.6  3.2  1.85  1.4  312  143                                            92   1.6  3.2  1.85  1.8  279  155                                            __________________________________________________________________________

A linear regression analysis was performed upon the above data, withcorrelation coefficients (r) calculated for certain variables. Thisanalysis showed a definite correlation between magnesium exchangecapacity and average particle size (r =-0.581). Based on this sample,there is less than a 1% probability that no correlation exists betweenthese two variables. There is less than a 1% probability that there isno correlation between silica to alumina molar ratio and averageparticle size (r =-0.405); between sodium oxide to alumina molar ratioand average particle size (r =-0.469); and between alumina concentrationand average particle size (r =+0.465). Thus, the average particle sizeand the magnesium exchange capacity can be controlled by adjustingeither the silica to alumina molar ratio or the sodium oxide to aluminamolar ratio or the alumina concentration.

                  TABLE VII                                                       ______________________________________                                        ZEOLITE A - PARTICLE CHARACTERISTICS                                                        Micron                                                               Average  Range                                                           Ex-  Particle of at least                                                                              Cumulative                                           am-  Size     90% of     % Less Than                                          ple  Microns  Weight     One Micron                                                                             Other                                       ______________________________________                                        1    2.4      1.0-4.0    19       Max 5% > 3.2μ                            2    0.9      0.1-2.0    96       Max 5% > 1.25μ                           3    1.25     0.1-2.5    67       Max 1% > 2.0μ                            4    0.86     0.1-1.6    92       Max 1% > 2.0μ                            5    1.4      0.1-2.5    58       Max 2% > 2.5μ                            6    2.1      0.1-4.0    35       Max 5% > 2.5μ                            7    1.1      0.1-2.5    86       Max 1% > 1.6μ                            8    1.5      0.1-2.5    58       Max 1% > 2.5μ                            9    2.4      0.1-5.0    61       Max 1% > 3.2μ                            10   0.9      0.1-2.0    92       Max 1% > 1.6μ                            11   1.3      0.1-3.2    68       Max 1% > 2.0μ                            12   1.4      0.1-2.5    56       Max 1% > 2.5μ                            13   0.93     0.1-2.5    92       Max 1% > 1.6μ                            14   1.2      0.1-2.5    73       Max 1% > 2.0μ                            15   1.5      0.1-3.2    55       Max 1% > 2.5μ                            16   0.9      0.1-2.5    93       Max 1% > 1.6μ                            17   1.4      0.1-3.2    64       Max 1% > 2.0μ                            18   1.5      0.1-3.2    53       Max 1% > 2.5μ                            19   0.7      0.1-1.6    98       Max 1% > 1.3μ                            20   2.0      0.1-4.0    39       Max 1% > 3.2μ                            21   1.1      0.1-2.5    97       Max 1% > 1.6μ                            22   0.8      0.1-1.6    95       Max 1% > 1.6μ                            23   0.84     0.1-2.0    94       Max 1% > 1.3μ                            24   0.95     0.1-2.0    96       Max 1% > 1.3μ                            25   1.0      0.1-2.0    96       Max 1% > 1.3μ                            26   0.7      0.1-2.0    98       Max 1% > 1.3μ                            27   0.8      0.1-2.0    96       Max 1% > 1.25μ                           28   1.3      0.1-2.5    71       Max 1% > 2.0μ                            29   1.0      0.1-2.5    88       Max 1% > 1.6μ                            30   1.5      0.1-3.2    55       Max 1% > 2.5μ                            31   0.75     0.1-2.0    97       Max 1% > 1.3μ                            32   0.86     0.1-2.0    96       Max 1% > 1.3μ                            33   0.93     0.1-2.0    97       Max 1% > 1.25μ                           34   1.1      0.1-2.0    83       Max 1% > 2.0μ                            35   1.7      0.1-4.0    46       Max 1% > 2.5μ                            36   0.88     0.1-2.0    96       Max 1% > 1.3μ                            37   1.4      0.1-3.2    73       Max 1% > 2.0μ                            38   0.85     0.1-2.5    94       Max 1% > 1.6μ                            39   1.7      0.1-4.0    50       Max 1% > 2.5μ                            40   0.95     0.1-2.0    97       Max 1% > 1.3μ                            41   0.94     0.1-2.0    94       Max 1% > 1.6μ                            42   1.1      0.1-2.0    82       Max 1% > 1.6μ                            43   0.8      0.1-2.0    96       Max 1% > 1.3μ                            44   0.9      0.1-2.0    97       Max 1% > 1.6μ                            45   1.1      0.1-3.2    94       Max 1% > 1.6μ                            46   1.3      0.1-3.2    77       Max 1% > 2.0μ                            47   0.87     0.1-2.0    96       Max 1% > 1.3μ                            48   1.7      0.1-4.0    54       Max 1% > 2.5μ                            49   1.0      0.1-2.0    86       Max 1% > 1.6μ                            50   1.0      0.1- 1.6   80       Max 1% > 1.6μ                            51   0.9      0.1-1.6    90       Max 1% > 1.6μ                            52   0.84     0.1-1.6    95       Max 1% > 1.6μ                            53   1.1      0.1-2.0    97       Max 1% > 1.6μ                            54   1.1      0.1-2.5    86       Max 1% > 2.0μ                            55   0.92     0.1-2.0    95       Max 1% > 1.6μ                            56   1.3      0.1-3.2    71       Max 1% > 2.0μ                            57   2.0      0.1-5.0    40       Max 1% > 3.2μ                            58   0.9      0.1-2.0    96       Max 1% > 1.6μ                            59   1.1      0.1-2.0    96       Max 1% > 1.6μ                            60   0.95     0.1-2.5    95       Max 1% > 1.6μ                            61   1.1      0.1-2.0    95       Max 1% > 1.6μ                            62   1.2      0.1-3.2    80       Max 1% > 2.0μ                            63   1.0      0.1-2.5    92       Max 1% > 1.6μ                            64   1.7      0.1-4.0    56       Max 1% > 2.5μ                            65   1.1      0.1-2.0    95       Max 1% > 1.6μ                            66   0.9      0.1-2.0    97       Max 1% > 1.6μ                            67   1.2      0.1-2.0    85       Max 1% > 1.6μ                            68   1.5      0.1-3.2    53       Max 1% > 2.5μ                            69   1.4      0.1-3.2    51       Max 5% > 2.0μ                            70   1.4      0.1-3.2    54       Max 4% > 2.0μ                            71   1.7      0.1-4.0    62       Max 2% > 2.5μ                            72   1.1      0.1-3.2    91       Max 1% > 2.0μ                            73   0.95     0.1-2.0    95       Max 1% > 1.6μ                            74   1.4      0.1-3.2    95       Max 1% > 1.6μ                            75   1.2      0.1-3.2    80       Max 1% > 2.0μ                            76   2.0      0.1-5.0    48       Max 1% > 3.2μ                            77   1.3      0.1-3.2    76       Max 1% > 2.0μ                            78   1.2      0.1-3.2    76       Max 1% > 3.2μ                            79   2.2      0.1-5.0    34       Max 1% > 3.2μ                            80   1.6      0.1-4.0    80       Max 5% > 1.6μ                            81   1.4      0.1-4.0    95       Max 1% > 2.0μ                            82   1.3      0.1-3.2    79       Max 1% > 2.0μ                            83   1.0      0.1-5.0    57       Max 1% > 3.2μ                            84   1.2      0.1-3.2    86       Max 1% > 2.0μ                            85   1.6      0.1-4.0    80       Max 1% > 2.0μ                            86   0.92     0.1-2.0    98       Max 1% > 1.25μ                           87   1.4      0.1-3.2    77       Max 1% > 2.0μ                            88   1.6      0.1-4.0    71       Max 1% > 2.5μ                            89   1.97     0.1-2.5    91       Max 1% > 1.6μ                            90   1.2      0.1-3.2    95       Max 1% > 1.6μ                            91   1.4      0.1-3.2    67       Max 1% > 2.5μ                            92   1.8      0.1-4.0    53       Max 1% > 2.5μ                            ______________________________________                                    

The following examples for preparation of small particle size zeolite Awere carried out to illustrate the use of molar ratios of SiO₂ :Al₂ O₃in the range of 1:1 to 1.5:1.

                                      TABLE VIII                                  __________________________________________________________________________    COMPOSITION OF REACTION MIXTURE                                               FOR PREPARATION OF ZEOLITE A                                                       Water/                                                                            Sodium                                                                    Sodium                                                                            Oxide/                                                                            Silica                                                                             Silicate Solution                                                                       Aluminate Solution                                Example                                                                            Oxide                                                                             Silica                                                                            Alumina                                                                            % Na.sub.2 O                                                                       % SiO.sub.2                                                                        % Na.sub.2 O                                                                       % Al.sub.2 O.sub.3                           __________________________________________________________________________    93   15  1.6 1.5  10.6 25.8 17.4 15.9                                         94   25  1.6 1.5  5.5  13.4 14.9 13.6                                         95   15  2.4 1.5  8.3  20.2 19.8 10.8                                         96   25  2.4 1.5  3.3   8.2 19.8 10.8                                         97   20  2.4 1.0  6.2  15.3 15.9 13.0                                         98   20  2.0 1.0  8.5  20.8 13.9 14.2                                         99   25  2.4 1.0  4.0   9.8 15.9 13.0                                         100  25  2.0 1.0  5.2  12.8 13.9 14.2                                         __________________________________________________________________________

                  TABLE IX                                                        ______________________________________                                        REACTION CONDITIONS - ZEOLITE A                                                                            Reac-   Reac-                                                                 tion    tion                                     Preheating Temp °C.                                                                      Time of    Temp.   Time -                                   Example                                                                              Silicate Aluminate Addition Sec                                                                           20 C. Hrs                                  ______________________________________                                        93     70       70        30       80    1.5                                  94     50       50        30       60    6.0                                  95     50       50        30       60    3.5                                  96     50       50        30       60    4.0                                  97     50       50        30       60    5.0                                  98     50       50        30       60    6.5                                  99     50       50        30       60    5.0                                  100    50       50        30       60    7.0                                  ______________________________________                                    

                  TABLE X                                                         ______________________________________                                        PARTICLE CHARACTERIZATION - ZEOLITE A                                                        Micron                                                               Average  Range                                                                Particle of at least                                                                             Cumulative                                           Ex-   Size     90% of    % Less Than                                          ample Microns  Weight    One Micron                                                                             Other                                       ______________________________________                                        93    2.2      0.1-5.0   58       Max 1% > 3.2μ                            94    1.8      0.1-4.0   33       Max 1% > 3.2μ                            95    1.7      0.1-4.0   44       Max 1% > 2.5μ                            96    1.5      0.1-2.5   56       Max 1% > 2.5μ                            97    1.2      0.1-2.5   74       Max 1% > 2.0μ                            98    1.3      0.1-3.2   73       Max 1% > 2.0μ                            99    1.1      0.1-2.5   82       Max 1% > 2.0μ                            100   1.4      0.1-3.2   69       Max 1% > 2.0μ                            ______________________________________                                    

                  TABLE XI                                                        ______________________________________                                        EXCHANGE CAPACITY FOR ZEOLITE A                                                       Average                  Magnesium                                    Example Diameter μ                                                                             Calcium Capacity                                                                           Capacity                                     ______________________________________                                        93      2.2         298          93                                           94      1.8         296          111                                          95      1.7         294          100                                          96      1.5         311          134                                          97      1.2         291          93                                           98      1.3         270          96                                           99      1.1         289          121                                          100     1.4         270          114                                          ______________________________________                                    

As may be seen from Examples 1 to 92, the following are preferred molarratios for production of zeolite A at reaction temperatures of 60° to100° C.:

    ______________________________________                                        Water to Sodium Oxide                                                                           15.0 to 30.0                                                Sodium Oxide to Silica                                                                          1.2 to 3.0                                                  Silica to Alumina 2.0 to 7.3                                                  ______________________________________                                    

In addition, Examples 93-100 illustrate a further preferred combinationof conditions for production of small particle size zeolite A: usingreaction temperatures of 60° to 80° C., reaction times of 1.5 to 7.0hours, and the following molar ratios:

    ______________________________________                                        Water to Sodium Oxide                                                                           15.0 to 25.0                                                Sodium Oxide to Silica                                                                          1.6 to 2.4                                                  Silica to Alumina 1.0 to 1.5                                                  ______________________________________                                    

In Tables XII, XIII, XIV and XV, the following are examples forproduction of zeolites similar to zeolite X and characterization of theproducts.

Thereafter in Tables XVI, XVII, XVIII and XIX, are examples forpreparation of zeolite mixtures similar to mixtures of zeolite A andzeolite X and characterization of the products. These tables also setforth the exchange capacities of the products.

                                      TABLE XII                                   __________________________________________________________________________    COMPOSITION OF REACTION MIXTURE                                               FOR THE PREPARATION OF ZEOLITE X                                                   Water/                                                                            Sodium                                                                    Sodium                                                                            Oxide/                                                                            Silica/   % Sodium                                               Example                                                                            Oxide                                                                             Silica                                                                            Alumina                                                                            % Water                                                                            Oxide % Silica                                                                           % Alumina                                   __________________________________________________________________________    101  30  1.7 7.3  94.73                                                                              3.16  1.86 0.25                                        102  30  1.6 7.3  94.61                                                                              3.15  1.97 0.27                                        103  30  1.5 7.3  94.46                                                                              3.15  2.10 0.29                                        104  30  1.5 7.3  94.46                                                                              3.15  2.10 0.29                                        105  30  1.5 5.3  94.36                                                                              3.15  2.10 0.40                                        106  30  1.4 7.3  94.30                                                                              3.14  2.25 0.31                                        __________________________________________________________________________

                  TABLE XIII                                                      ______________________________________                                        REACTION CONDITIONS - ZEOLITE X                                               Temperature °C.                                                                          Time of  Reaction Reaction                                         Silicate Aluminate Addition                                                                             Temp.  Time                                  Example                                                                              Solution Solution  (sec)  °C.                                                                           (Hrs)                                 ______________________________________                                        101    90       90        30     100    8.0                                   102    90       90        30     100    6.0                                   103    90       90        30     100    8.0                                   104    90       90        30     100    8.0                                   105    90       90        30     100    8.0                                   106    90       90        30     100    8.0                                   ______________________________________                                    

                  TABLE XIV                                                       ______________________________________                                        ZEOLITE PARTICLE CHARACTERIZATION                                                                 Micron Range of                                                                            Cumulative %                                        Average Particle                                                                           at Least 90% Less Than                                    Example                                                                              Size - Micron                                                                              of Weight    One Micron                                   ______________________________________                                        101    2.0          0.1-5.0      48                                           102    1.7          0.1-3.2      49                                           103    2.2          0.1-4.0      41                                           104    2.8          0.1-6.0      46                                           105    2.2          0.1-4.0      45                                           106    1.5          0.1-3.2      52                                           ______________________________________                                    

                  TABLE XV                                                        ______________________________________                                        EXCHANGE CAPACITY FOR ZEOLITE X                                               Ex-           Sodium   %                  Mag-                                am-  Silica/  Oxide/   Alu- Average                                                                              Calcium                                                                              nesium                              ple  Aluimina Alumina  mina Diameter                                                                             Capacity                                                                             Capacity                            ______________________________________                                        101  7.3      12.4     0.25 2.0    244    135                                 102  7.3      11.7     0.27 1.7    227    140                                 103  7.3      11.0     0.29 2.2    228    139                                 104  7.3      11.0     0.29 2.8    209    136                                 105  5.3       8.0     0.40 2.2    225    140                                 106  7.3      10.2     0.31 1.5    235    155                                 ______________________________________                                    

                  TABLE XVI                                                       ______________________________________                                        COMPOSITION OF REACTION MIXTURE FOR                                           THE PREPARATION OF ZEOLITE A AND ZEOLITE X                                    Ex-  Water/  Sodium               %           %                               am-  Sodium  Oxide/  Silica/                                                                              %     Sodium                                                                              %     Alu-                            ple  Oxide   Silica  Alumina                                                                              Water Oxide Silica                                                                              mina                            ______________________________________                                        107  30      2.0     7.3    95.03 3.17  1.58  0.22                            108  30      1.9     7.3    94.94 3.17  1.67  0.23                            109  30      1.8     7.3    94.84 3.16  1.76  0.24                            110  30      1.7     6.3    94.69 3.16  1.86  0.30                            111  30      1.7     5.3    94.64 3.16  1.86  0.35                            112  30      1.6     6.3    94.57 3.15  1.97  0.31                            113  30      1.7     5.3    94.51 3.15  1.97  0.37                            114  30      1.5     5.3    94.36 3.15  2.10  0.40                            115  30      1.5     3.3    94.14 3.14  2.09  0.63                            116  30      1.5     2.5    93.95 3.13  2.09  0.84                            117  30      1.5     2.5    93.95 3.13  2.09  0.84                            ______________________________________                                    

                  TABLE XVII                                                      ______________________________________                                        REACTION CONDITIONS - ZEOLITES A & X                                          Ex-                    Time of                                                am-  Temps.  °C.                                                                              Addition                                                                              Reaction                                                                              Reaction                               ple  Silicate                                                                              Aluminate (sec.)  Temp. °C.                                                                      Time (Hrs.)                            ______________________________________                                        107  90      90        30      100     4.0                                    108  90      90        30      100     4.0                                    109  90      90        30      100     4.0                                    110  90      90        30      100     6.0                                    111  90      90        30      100     4.0                                    112  90      90        30      100     6.0                                    113  90      90        30      100     8.0                                    114  95      95        300*    100     5.0                                    115  90      90        30      100     4.0                                    116  90      90        30      100     4.0                                    117  90      90        300     100     6.0                                    ______________________________________                                         *Silicate and Aluminate Solutions Combined Simultaneously.               

                  TABLE XVIII                                                     ______________________________________                                        ZEOLITES A & X - PARTICLE CHARACTERIZATION                                    Ex-  Average                                                                  am-  Particle   Micron Range of at                                                                           Cumulative % Less                              ple  Size - Micron                                                                            Least 90% of Weight                                                                          Than One Micron                                ______________________________________                                        107  2.0        0.1-4.0        45                                             108  1.7        0.1-3.2        48                                             109  1.8        0.1-4.0        40                                             110  1.9        0.1-3.2        38                                             111  1.9        0.1-4.0        41                                             112  2.7        0.1-5.0        41                                             113  2.7        0.1-4.0        42                                             114  3.3        0.1-6.4        42                                             115  2.9        0.1-5.0        42                                             116  4.0        0.1-8.0        37                                             117  5.4        0.1-10.0       44                                             ______________________________________                                    

                  TABLE XIX                                                       ______________________________________                                        EXCHANGE CAPACITY FOR A                                                       COMBINATION OF ZEOLITE A AND ZEOLITE X                                                                            Cal-                                      Ex-           Sodium                cium  Mag-                                am-  Silica/  Oxide/   % Alu-                                                                              Average                                                                              Capa- nesium                              ple  Alumina  Alumina  mina  Diameter                                                                             city  Capacity                            ______________________________________                                        107  7.3      14.6     0.22  2.0    255   130                                 108  7.3      13.9     0.23  1.7    240   135                                 109  7.3      13.1     0.24  1.8    228   139                                 110  6.3      10.7     0.34  1.9    224   141                                 111  5.3       9.0     0.35  1.9    229   138                                 112  6.3      10.1     0.31  2.7    221   130                                 113  5.3       8.5     0.37  2.7    304   130                                 114  5.3       8.0     0.40  3.3    235   143                                 115  3.3       5.0     0.63  2.9    257   150                                 116  2.5       3.8     0.84  4.0    256   118                                 114  2.5       3.8     0.84  5.4    303   129                                 ______________________________________                                    

The following examples illustrate activation of the silicate solutionwith alumina.

EXAMPLE 118

A sodium silicate solution of composition 3.4% sodium oxide and 8.5%silica was activated with 600 ppm alumina from a sodium aluminatesolution. At a temperature of 70° C., a sodium aluminate solution, alsoat 70° C., of composition 24.2% sodium oxide and 8.3% alumina, was addedto the sodium silicate within thirty seconds. The resulting gel wasbroken down by agitation until a homogeneous slurry was obtained. Thebatch was then reacted at 80° C. for 2.5 hours. The total batchcomposition had a water to sodium oxide molar ratio of 25:1, a sodiumoxide to silica molar ratio of 2:1 and a silica to alumina molar ratioof 3:1. The resulting product was zeolite A which exhibited a calciumion exchange capacity of 277 and magnesium ion exchange capacity of 175.The resulting zeolite particles exhibited a narrow differential weightpercent gaussian distribution with an average particle size of 1.1microns with at least 90% of the weight between 0.1 and 2.0 microns. Thecumulative percent population exhibited 78% less than one micron, withno more than 2% greater than 1.6 microns.

EXAMPLE 119

A sodium silicate solution of composition 4.0% sodium oxide and 10.0%silica was activated with 600 ppm alumina from a sodium aluminatesolution. At a temperature of 70° C., a sodium aluminate solution, alsoat 70° C., of composition 25.6% sodium oxide and 7.5% alumina, was addedto the sodium silicate within thirty seconds. The resulting gel wasbroken down by agitation until a homogeneous slurry was obtained. Thebatch was then reacted at 80° C. for 22 hours. The total batchcomposition had a water to sodium oxide molar ratio of 30:1, a sodiumoxide to silica molar ratio of 1:2 and a silica to alumina molar ratioof 7:1. The resulting product was zeolite X which exhibited both acalcium ion exchange capacity at 252 and magnesium ion exchange capacityof 147. The resulting zeolite particles exhibited a narrow differentialweight percent gaussian distribution with an average particle size of2.0 microns with at least 90% of the weight between 0.1 and 3.2 microns.The cumulative precent population exhibited 52% less than one micron,with no more than 1% greater than 4.0 microns.

EXAMPLE 120

A sodium silicate solution of composition 3.6% sodium oxide and 9.0%silica was activated with 600 ppm alumina from a sodium aluminatesolution. The sodium silicate was then heated to 70° C. for thirtyminutes. At that time a sodium aluminate solution, also at 70° C., ofcomposition 29.5% sodium oxide and 5.3% alumina, was added to the sodiumsilicate within thirty seconds. The resulting gel was broken down byagitation until a homogeneous slurry was obtained. The batch was thenreacted at 80° C. for six hours. The total batch composition had a waterto sodium oxide molar ratio of 25:1, a sodium oxide to silica molarratio of 1.7:1 and a silica to alumina molar ratio of 7:1. The resultingproduct was a combination of 40% zeolite X and 60% zeolite A. Thisproduct exhibited a calcium ion exchange capacity of 284 and magnesiumion exchange capacity of 139. The resulting zeolite particles exhibiteda narrow differential weight percent gaussian distribution with anaverage particle size of 0.8 microns with at least 90% of the weightbetween 0.1 and 3.2 microns. The cumulative precent population exhibited90% less than one micron, with no more than 1% greater than 1.3 microns.

EXAMPLE 121

A sodium silicate solution of composition 11.2% sodium oxide and 27.15%silica was activated with 500 ppm alumina from a sodium aluminatesolution. The sodium silicate was then heated to 90° C. for thirtyminutes. At that time a sodium aluminate solution, also at 90° C., ofcomposition 10.4% sodium oxide and 14.6% alumina was added to the sodiumsilicate within thirty seconds. The resulting gel was broken down byagitation until a homogeneous slurry was obtained. The batch was thenreacted at 100° C. for 24 hours. The total batch composition had asodium oxide to silica molar ratio of about 0.56:1, a silica to aluminamolar ratio of about 7.8:; and a water to sodium oxide molar ratio ofabout 20:1. The resulting product was zeolite Y with a silica to aluminamolar ratio of 5.2:1.

Thus, in operation, either zeolite X, zeolite A, a combination of thetwo, or zeolite Y can be formed by dissolving sand in a sodium hydroxidesolution to form a sodium silicate solution, activating it with alumina,forming a sodium aluminate solution and quickly adding the sodiumaluminate solution to the activated sodium silicate solution.

WATER SOFTENING COMPOSITIONS

As indicated above, the small particle size zeolites of the inventionare useful in several areas. Thus, a water soluble softening compositioncan be formed containing a binding agent, a solubilizing agent, waterand the zeolites of the present invention. Zeolite A, zeolite X or acombination of the two can be used. In these compositions, sodiumsilicate may be used as the binding agent, with the silica to sodiumoxide ratio being between 1:1 and 3.3:1, preferably about 2.5:1 sincethat is the most common molar ratio found in detergent formulations. Atleast 1% sodium silicate is required to bind the bead, but more than 20%sodium silicate limits the amount of sodium silicate that can be addedto the system without enough improvement in bead strength to justify thelower aluminosilicate levels. The most preferred binding agent would bea sodium polysilicate having a silica to sodium oxide ratio of 2.5:1.About 1% to 20% of a suitable solubilizing agent should be presentincluding soluble sodium phosphates, carbonates, bicarbonates,tetraborates and sodium sulfate. The preferred solubilizing agent issodium sulfate.

Some water is needed in the water softening bead. Otherwise the ionexchange capacity of the sodium silicate is reduced. In a preferredembodiment of the present invention, at least 66% by weight of ananhydrous basis of zeolite of this invention is added to 1 to 20% byweight of sodium sulfate and the remainder is water. This slurry is thendried with nozzle atomization in a spray dryer at inlet temperatures ofbelow 540° C. to produce beads. If the beads are dried at a temperatureof above 540° C. some ion exchange capacity can be lost.

DETERGENT COMPOSITIONS

A detergent composition can be formed containing a high magnesiumexchange capacity. Zeolite A, zeolite X, or a combination of thesezeolites of the invention are used in a preferred aspect by spraying aliquid surfactant onto the zeolite to form a free-flowing powder orpellets. Care must be taken not to exceed the absorbency limits of thepigment. The powder or pellets are then added to detergent formulationswithout further drying. The powder or pellets are dry blended into a drydetergent formulation.

The surfactant can be anionic, non-ionic or amphoteric although thesurfactants include the higher alkyl aryl sulfonic acids and theiralkali metal and alkaline earth metal salts such as, for example, sodiumdodecyl benzene sulfonate, sodium tridecyl sulfonate, magnesium dodecylbenzene sulfonate, potassium tetradecyl benzene sulfonate, ammoniumdodecyl toluene sulfonate, lithium pentadecyl benzene sulfonate, sodiumdioctyl benzene sulfonate, disodium dodecyl benzene disulfonate,disodium diisopropyl naphthalene disulfonate and the like, as well asthe alkali metal salts of fatty alcohol esters of sulfuric and sulfonicacids, the alkali metal salts of alkyl aryl (sulfothioic acid) estersand the alkyl thiosulfuric acid

Non-ionic surface active compounds, such as those products produced bycondensing one or more relatively lower alkyl alcohol amines, such asmethanolamine, ethanolamine, propanolamine, with a fatty acid such aslauric acid, cetyl acid, tall oil fatty acid, abietic acid, to producethe corresponding amide may also be used. In addition, amphotericsurface active compounds such as sodium N-coco beta amino propionate,sodium N-tallow beta amino dipropionate, sodium N-lauryl betaiminodipropionate and the like may also be used.

The use of small particle size zeolite A was evaluated by substitutingit for phosphate in basic detergent formulations. Washing tests wereconducted in a terg-o-tometer, Model 7243, machine. Tests were run at0.15% detergent concentration in 120 and 240 ppm hard water (Ca:Mg=2:1)at 120° F. A wash time of fifteen minutes at 125 rpm with twofive-minute rinses was used. Detergency was determined on soiled testcloths of cotton, spun dacron, cotton/dacron with permanent press, andcotton shirting wash and wear. The detergency value was determined byusing a Gardner Model XL-10 reflectometer to measure reflectance beforeand after washing. The results on Table XX indicate that small particlesize zeolite A can replace phosphates in detergent formulations and mayeven improve overall detergency. This is particularly evident in the 240ppm hardness test. It is believed that the favorable results obtained inthese tests can be attributed to the ability of small particle sizezeolite A to remove both calcium and magnesium ions from solution atextremely rapid rates.

                                      TABLE XX                                    __________________________________________________________________________    USE OF SMALL PARTICLE SIZE ZEOLITE A IN DETERGENTS                                     120 ppm Hardwater                                                                             240 ppm Hardwater                                             #1      #2      #3      #4                                           FORMULATION                                                                            wt %                                                                              gms wt %                                                                              gms wt %                                                                              gms wt %                                                                              gms                                      __________________________________________________________________________    Sodium   25  .375                                                                              --  --  25  .375                                                                              --  --                                       Tripolyphosphate                                                              Small particle                                                                         --  --  25  *.469                                                                             --  --  25  *.469                                    size Zeolite A                                                                (Example 35)                                                                  Richonate 45B                                                                          12  .18 12  .18 12  .18 12  .18                                      Richonal A                                                                              5  .075                                                                               5  .075                                                                               5  .075                                                                               5  .075                                     Condensate Co                                                                           3  .045                                                                               3  .045                                                                               3  .045                                                                               3  .045                                     Carboxymethyl-                                                                          1  .015                                                                               1  .015                                                                               1  .015                                                                               1  .015                                     cellulose                                                                     Sodium Silicate                                                                        15  .225                                                                              15  .225                                                                              15  .225                                                                              15  .225                                     Sodium Sulfate                                                                         39  .585                                                                              39  .585                                                                              39  .585                                                                              39  .585                                     __________________________________________________________________________            120 ppm Hardwater 240 ppm Hardwater                                   RESULTS -                                                                             #1       #2       #3       # 4                                        Test Cloth                                                                            % Improvement                                                                          % Improvement                                                                          % Improvement                                                                          % Improvement                              __________________________________________________________________________    Cotton  32.8     39.0     33.4     34.1                                       Spun Dacron                                                                            3.0     15.8     10.7     42.4                                       Cotton/Dacron                                                                         17.8     17.2     18.8     20.2                                       permanent press                                                               Cotton shirting                                                                       22.8     19.9     19.7     24.8                                       wash and wear                                                                 % Total 76.4     91.9     82.6     121.5                                      Detergency                                                                    __________________________________________________________________________     *Active basis                                                            

PAPER COMPOSITIONS

Paper compositions can also be formed containing zeolites of small anduniform size of this invention, including zeolite A, zeolite X, or acombination of the two. The use of small particle size zeolite A as afiller in fine paper was evaluated by adding it to various types offurnishes. These furnishes included both bleached and unbleached pulps.Handsheets of various basis weights and different types of pulp weremade using a Nobel and Wood Sheet machine. Tests on these handsheetswere done according to the following TAPPI (The American Pulp and PaperInstitute) standards:

T-425m--Opacity of Paper

T-452m--Brightness of Paper and Paperboard

T-410m--Basis Weight of Paper and Paperboard.

Table XXI indicates that single pass retention of zeolite A is notdependent on size and that its retention is significantly higher thanHydrex, a registered trademark of the J. M. Huber Corporation, for anamorphous sodium magnesium aluminosilicate. This suggests that themechanism of zeolite A retention is different and that it is functionalto species rather than size. It is reasonable to suspect that theretention mechanism is due to a charge effect between the crystallinematerial and the pulp rather than mechanical effects. Surprisingly, thesmall particle size zeolite A of the present invention showed markedlybetter optical effects in both brightness and opacity than commercialzeolite A and was equal to the best known synthetic (Hydrex) used forthis application.

                                      TABLE XXI                                   __________________________________________________________________________    USE OF SMALL PARTICLE SIZE ZEOLITE A AS A FILLER IN FINE PAPER                               BASIS WT. %      TAPPI                                                        25 × 38 × 500                                                               PIGMENT                                                                              BRIGHT-                                                                             TAPPI                                   PIGMENT % FILLER                                                                             #/REAM                                                                              g/sq m                                                                            RETAINED                                                                             NESS  OPACITY                                 __________________________________________________________________________    Unfilled       50.9  75.3       85.0  82.8                                    Small Particle                                                                        3      52.1  77.1                                                                              58     86.7  86.5                                    Size                                                                          Zeolite A                                                                             6      50.2  74.3                                                                              55     88.2  89.0                                    (Example 10)                                                                          9      51.3  75.9                                                                              53     89.3  90.6                                    Commercial                                                                            3      50.8  75.2                                                                              56     85.6  84.6                                    Zeolite A                                                                             6      52.2  77.3                                                                              55     86.1  86.1                                            9      53.5  79.2                                                                              56     86.5  87.2                                    Unfilled       48.9  72.4       85.5  82.2                                    Small Particle                                                                        3      51.5  76.2                                                                              41     87.4  86.1                                    Size                                                                          Zeolite A                                                                             6      51.3  75.9                                                                              38     88.8  88.5                                    (Example 10)                                                                          9      51.4  76.1                                                                              34     89.9  90.1                                    Hydrex* 3      50.1  74.1                                                                              28     87.4  86.1                                            6      50.2  74.3                                                                              30     88.7  88.2                                            9      49.8  73.3                                                                              31     89.6  89.4                                    __________________________________________________________________________     *Registered Trademark of J. M. Huber Corporation                         

The use of small particle size zeolite A of this invention as anextender for titanium dioxide in paper was evaluated by adding it to ableached pulp paper furnish. The paper furnish was 50% bleached hardwoodand 50% bleached softwood Kraft. Handsheets were made and the propertieswere tested following the previously described procedures. Table XXIIshows the single pass retention of zeolite A in combination withtitanium dioxide. This data also suggests a different mechanism ofretention and confirms the results obtained in a single filler system.Optical properties obtained using small particle size zeolite A weresignificantly better than larger size material (commerical zeolite A)and equal to Hydrex.

                                      TABLE XXII                                  __________________________________________________________________________    USE OF SMALL PARTICLE SIZE ZEOLITE A AS AN EXTENDER                           FOR TITANIUM DIOXIDE IN FINE PAPER                                                            BASIS WT.                                                                     85 × 38 × 500                                                                      BRIGHT-                                      PIGMENT  FILLER # REAM                                                                              g/sq m                                                                            RETAINED                                                                             NESS  OPACITY                                __________________________________________________________________________    Unfilled        50.9  75.3       85.0  82.8                                   50% Small                                                                              3      50.6  74.9                                                                              61     87.8  88.4                                   Particle Size                                                                 Zeolite A                                                                              6      51.0  75.5                                                                              58     89.6  91.9                                   (Example 10)                                                                  and 50%  9      50.7  75.0                                                                              55     90.8  93.8                                   Titanium Dioxide                                                              50% Commerical                                                                         3      50.5  74.7                                                                              59     87.2  87.7                                   Zeolite A and                                                                          6      51.3  75.9                                                                              60     88.7  91.0                                   50% Titanium                                                                           9      51.4  76.1                                                                              60     89.7  92.9                                   Dioxide                                                                       Unfilled        48.9  72.4       85.5  82.2                                   50% Small                                                                              3      51.5  76.2                                                                              47     88.3  88.2                                   Particle Size                                                                 Zeolite A                                                                              6      51.0  75.5                                                                              42     89.8  91.4                                   (Example 10)                                                                  and 50%  9      50.3  74.4                                                                              40     90.9  93.4                                   Titanium Dioxide                                                              50% Hydrex and                                                                         3      50.3  74.4                                                                              24     88.3  88.5                                   50% Titanium                                                                           6      49.9  73.9                                                                              36     89.8  91.7                                   Dioxide  9      49.5  73.3                                                                              39     90.9  93.5                                   __________________________________________________________________________

The use of small particle size zeolite A as a filler in newsprint wasevaluated by adding it to a standard newsprint furnish. Newsprinthandsheets consisting of 65% groundwood and 35% semi-bleached Kraftpaper were made using the Noble and Wood Sheet machine. The sheets wereprinted at a pick-up of 1.7 and 2.5g ink/sq. m using a VandercookProofing Press with a solid block and a 4 mil impression pressure. After24 hours, brightness readings on the reverse side of printed andunprinted sheets were made. These were then plotted and results reportedas strike-through values at 20g ink/sq. m (modified version of theLarocque strike-through test).

The data on Table XXIII also indicates that the retention mechanism ofzeolite A is different than other specialty fillers commonly used fornewsprint applications. The results also confirm that small particlesize zeolite A is superior to commercial zeolite A and comparesfavorably with Zeolex 23, a registered trademark of the J. M. HuberCorporation, for an amorphous sodium aluminosilicate.

                                      TABLE XXIII                                 __________________________________________________________________________    USE OF SMALL PARTICLE SIZE ZEOLITE A IN NEWSPRINT                                                 Basis Wt.         TAPPI       S/T @                              %       %    24 × 36 × 500                                                               Caliper BRIGHT-                                                                             TAPPI 2 g/2                                                                              S/T                    PIGMENT                                                                              RETENTION                                                                             FILLER                                                                             #/REAM                                                                              g/sq m                                                                            MILS                                                                              MM  NESS  OPACITY                                                                             INK  REDUCTION              __________________________________________________________________________    Unfilled            28.8  46.9                                                                              3.0 0.76                                                                              59.3  83.7  17.1                        Small  37      2    30.1  49.0                                                                              3.1 .079                                                                              61.0  86.5  13.4 22                     Particle                                                                      Size   35      4    30.4  49.5                                                                              3.1 .079                                                                              62.3  88.0  10.4 39                     Zeolite A                                                                     Zeolex 23                                                                            29      2    28.8  46.9                                                                              3.0 .076                                                                              60.2  84.8  13.1 23                            35      4    29.5  48.0                                                                              3.0 .076                                                                              61.1  85.7   9.8 43                     Unfilled            29.6  48.2                                                                              3.3 .084                                                                              58.6  86.4  12.3                        Commercial                                                                           38      2    30.6  49.8                                                                              3.2 .081                                                                              59.2  87.7  11.4  7                     Zeolite A                                                                            43      4    31.3  50.9                                                                              3.2 .081                                                                              59.6  88.8  10.6 14                     __________________________________________________________________________

The use of small particle size zeolite A in paper coatings was tested invarious coating formulas. Two of these were as follows:

1.

87% Hydrasperse Clay

5% Titanium dioxide

8% Pigment

2.

92% Hydrasperse Clay

8% Pigment.

These formulations were prepared at 58% solids using 16 parts perhundred binder level (75% starch--25% Latex) and were ground using aCowles Dissolver. Paper used was a 32#base stock which was coated13#/3300 sq. ft. using a Keegan Laboratory Trailing Blade Coater. Allsheets were supercalendered 3 nips at 150 degrees Fahrenheit and 100psig. Sheets were then checked for gloss, opacity and brightness usingthe following TAPPI standards:

T--480m Gloss of Paper

T--425m Opacity of Paper

T--452, Brightness of Paper and Paperboard.

The results of Table XXIV show small particle size zeolite A to besuperior to commercial zeolite A. This is most obvious in better glossdevelopment, but there is also significant improvement in bothbrightness and opacity when used as either an extender for titanium oras a filler. Similar effects were seen in tests on coated board.

                  TABLE XXIV                                                      ______________________________________                                                   75 degree   TAPPI     TAPPI                                        Pigment    Gloss, %    Brightness                                                                              Opacity                                      ______________________________________                                        USE OF SMALL PARTICLE SIZE ZEOLITE A AS A                                     TITANIUM DIOXIDE EXTENDER IN PAPER COATINGS                                   (87% Hydrasperse Clay - 5% TiO.sub.2 8% Pigment)                              Small Particle                                                                           64.9        71.1      90.9                                         Size Zeolite A                                                                (Example 10)                                                                  Commercial 55.0        70.4      90.3                                         Zeolite A                                                                     ______________________________________                                        USE OF SMALL PARTICLE SIZE ZEOLITE A                                          AS A PIGMENT IN PAPER COATINGS                                                (92% Hydrasperse Clay - 8% Pigment)                                           Small Particle                                                                           64.0        69.3      89.0                                         Size Zeolite A                                                                (Example 10)                                                                  Commerical 55.9        68.1      88.5                                         Zeolite A                                                                     ______________________________________                                    

RUBBER COMPOSITIONS

A rubber composition can be formed containing zeolite A, zeolite X, or acombination of the two, of this invention.

The rubbers (alternatively referred to herein as elastomers, whichmaterials are unvulcanized) which can be employed in the inventioninclude both natural and synthetic rubbers. Exemplary of suitablesynthetic rubbers are styrene-butadiaene, butyl rubber, nitril rubber,polybutadiene, polyisoprene, ethylene propylene, acrylic, fluorocarbonrubbers, polysulfide rubbers and silicone rubbers. Mixtures ofcopolymers of the above synthetic rubbers can be employed alone or incombination with natural rubber. The preferred rubbers are nitrilerubber, styrene-butadiene rubber, natural rubber, polyisoprene, andmixtures thereof because they are most compatible with polyester fibers,although minor amounts of other rubbers can be included without adverseeffects. U.S. Pat. No. 3,036,980 is incorporated by reference to showthe formation of rubber compositions containing zeolites.

PLASTIC COMPOSITIONS

A plastic composition can be formed containing zeolites of small anduniform size. Either zeolite A, zeolite X, or a combination of the two,can be used.

NON-SETTLING FLATTING PIGMENT

The zeolite of this invention can also be used as non-settling flattingpigments. Either zeolite A, zeolite X, or a combination of the two, canbe used.

Small particle size zeolite A was evaluated as a non-settling, flattingpigment in nitrocellulose lacquer and as a prime pigment extender inflat latex paint systems. Tests in the nitrocellulose lacquer systemwere conducted by adding the zeolite to a lacquer. The amount of zeoliteused was equivalent to 10% by weight of vehicle solids. The lacquer andzeolite were blended together using a Hamilton Beach Model 936 Blenderat 16,000 rpm for four minutes and the resulting mixture was thenstrained through a fine mesh paint strainer. Hegman grind was determinedin the usual manner and the mixture was then drawn down on Leneta 5cpaper panels using a #34 wire wound coatings application rod. The panelswere dried at room temperature for 45 minutes under dust-free conditionsin a vertical position. A Gardner multiangle gloss meter was used todetermine gloss (60 degree head) and sheen (85 degree head) of thepanels. Settling was evaluated using an accelerated test with anarbitrary scale of 0 (fail) to 10 (none) after 7 days at 120° F.

The results on Table XXV show that small particle size zeolite A wassuperior to commercial zeolite A in all categories, and the exceptionalclarity of the lacquer containing small particle size zeolite A would beof significant value in specialty applications.

                  TABLE XXV                                                       ______________________________________                                        USE OF SMALL PARTICLE SIZE ZEOLITE A AS A                                     NON-SETTLING, FLATTING PIGMENT                                                IN NITROCELLULOSE LACQUER                                                                                     85°                                    Sample        Hegman   60° Gloss                                                                       Sheen Settling                                ______________________________________                                        Small Particle Size                                                                         6.25     15       27    8                                       Zeolite A (Example 10)                                                        Commercial Zeolite A                                                                        6.00     33       71    1                                       ______________________________________                                    

The use of small particle size zeolite A as a prime pigment extender inflat latex paint systems was evaluated as follows:

Part I of the formulation was mixed, Part II of the formulation was thenadded and the entire mixture was blended for 10 minutes on a Cowles highspeed mixer. The zeolite A was added at this time and dispersed for 5minutes. The letdown (Part III) was then added to complete theformulation and mixed for an additional 5 minutes. The resulting paintwas drawn down on Leneta 1B paper panels using a #34 wire wound coatingsapplication rod. The panels were dried at room temperature underdust-free conditions in a vertical position. A Gardner multi-angle glossmeter was used to determine the gloss and sheen of the panels.

                  TABLE XXVI                                                      ______________________________________                                                         Weight, gms                                                                              Weight, gms                                       Formulation      #1         #2                                                ______________________________________                                        Part I                                                                        Water            200        200                                               Cellosize OP-15000                                                                             0.5        0.5                                               AP-95            2          2                                                 Daxad 30         8          8                                                 Ethylene Glycol  17         17                                                Super Ad It      1          1                                                 Napco NDW        1          1                                                 Part II                                                                       R-901            150        150                                               Huber 70C        100        100                                               G-White          150        150                                               Small particle size                                                                            60         --                                                Zeolite A (Example 10)                                                        Commercial Zeolite A                                                                           --         60                                                Part III                                                                      Water            183        183                                               QP-15000         3          3                                                 AMP-95           3          3                                                 Texanol          8          8                                                 Napco NDW        2          2                                                 Amsco 3011       264        264                                               ______________________________________                                    

                  TABLE XXVII                                                     ______________________________________                                        USE OF SMALL PARTICLE SIZE ZEOLITE A AS A                                     PRIME PIGMENT EXTENDER IN FLAT LATEX SYSTEMS                                                Brightness,                                                                             Contrast 60°                                                                          85°                             Sample        YB        Ratio    Gloss Sheen                                  ______________________________________                                        Small Particle Size                                                                         89.6      0.968    3     7                                      Zeolite A (Example 10)                                                        Commercial Zeolite A                                                                        87.6      0.958    3     4                                      ______________________________________                                    

The results on Table XXVII indicate that small particle size zeolite Aperforms better than commercial zeolite A as a prime pigment spacer inthis paint system. This is evident by the brightness and contrast ratioswhich indicate that the small partical size zeolite A is significantlymore efficient and better performing in optical properties.

Zeolite Y of this invention has been found to have particularly goodadsorption characteristics as is demonstrated by the representativeadsorption data in Table XXVIII.

                  TABLE XXVIII                                                    ______________________________________                                        ADSORBATE DATA FOR ZEOLITE Y                                                            Pressure    Temperature                                                                              Weight %                                     Adsorbate (mm. Hg)    (°C.)                                                                             Adsorbed                                     ______________________________________                                        H.sub.2 O 25          25         35.2                                         CO.sub.2  700         25         26.0                                         n-pentane 200         25         14.9                                         (C.sub.4 F.sub.9).sub.3 N                                                               0.07        25         1.1                                          (C.sub.4 F.sub.9).sub.3 N                                                               1.5         50         21.4                                         Krypton   20          -183       70.0                                         Oxygen    700         -183       35.7                                         ______________________________________                                         The foregoing data were obtained in the following manner:

Samples of zeolite Y which had been activated by dehydration at atemperature of approximately 350° C., under vacuum, were tested todetermine their adsorptive properties. The adsorption properties weremeasured in a McBain-Baker adsorption system. The zeolite samples wereplaced in light aluminum buckets suspended from quartz springs. Theywere activated in situ, and the gas or vapor under test was thenadmitted to the system. The gain in weight of the adsorbent was measuredby the spring extensions as read by a cathetometer. In Table XXVIII thepressure given for each adsorption is the pressure of the adsorbate. Theterm "weight % adsorbed" in the table refers to the percentage increasein the weight of the activated adsorbent.

As may be seen from the adsorption data in the table, activated zeoliteY can be employed to separate molecules having a critical dimensiongreater than that of heptocosafluorotributylamine from molecules havingsmaller critical dimensions. The critical dimension of a molecule isdefined as the diameter of the smallest cylinder which will accomodate amodel of the molecule constructed using the best available van der Waalsradii, bond angles, and bond lengths.

A unique property of zeolite Y is its strong preference for polar,polarizable and unsaturated molecules, providing, of course, that thesemolecules are of a size and shape which permit them to enter the poresystem. This is in contrast to charcoal and silica gel which show aprimary preference based on the volatility of the adsorbate.

Zeolite Y is distinguished from other molecular sieve types, forexample, zeolite X described in U.S. Pat. No. 2,882,244, by itsexceptional stability toward steam at elevated temperatures. This is aproperty which makes zeolite Y particularly suitable for such processesas gas drying.

What is claimed is:
 1. A rubber composition which contains a filleramount of a synthetic zeolite, said zeolite being present in the form ofsmall particles said particles being similar to zeolite A in having thechemical formula of zeolite A but differing from zeolite A in havinglarger ports or pore diameters, having bimodal pore size distribution,and having an X-ray diffraction pattern depressed from that of a 4micron zeolite a standard, said particles being formed by the reactionof sodium silicate and sodium aluminate when the preparative batchreaction mixture has a water to sodium oxide molar ratio of between 15:1and 20:1; a sodium oxide to silica molar ratio of between 1.5:1 and3.1:1; and a silica to alumina molar ratio of between 1:0:1 and 4.5:1,and wherein the particles exhibit a narrow differential weight percentguassian distribution with an average particle size of no more thanabout 1.6 microns with at least 90% of the weight between 0.1 and 3.2microns in diameter, wherein the cumulative percent population exhibitsat least 64% by weight less than one micron, with no more than 1% byweight greater than 2.0 microns in diameter, said particles having asurface area of greater than 10 m² /g.
 2. A rubber composition accordingto claim 1 wherein said zeolite particles are produced from a batchreaction mixture comprising sodium silicate and sodium aluminate, orsodium hydroxide mother liquor and an amorphous sodium alumino silicate,in total having a water to sodium oxide molar ratio of between 15:1 and20:1; a sodium oxide to silicate molar ratio of between 1.5:1 and 3.1:1,and a silica to alumina molar ratio of between 1.0:1 and 4.5:1, whereinsaid mixture is reacted at a temperature of about 60 degrees Celsius to120 degrees Celsius; wherein said molar ratios and reaction temperatureare chosen from the values provided so as to produce zeolite particlesof average particle size in microns of less than 1.6 in accordance withthe following equation wherein ln is natural log:

    ______________________________________                                        Average ln                                                                            =     A(N/S × S/A) + B(H/N × Temp/100) +                  (Particle     C(S/A).sup.3 + D(S/A).sup.2 + E(H/N ÷ S/A) +                Size)         F(S/A) + G(Temp/100).sup.3 + H(H/N ÷ N/S) +                               I(N/S).sup.2 + J(N/S ÷ S/A) + K                             ______________________________________                                    

wherein: H/N--Moles of H₂ O÷moles Na₂ O present in the batch; N/S--MolesNa₂ O÷moles SiO₂ present in the batch; S/A--Moles SiO₂ ÷moles Al₂ O₃present in the batch; Temp--Reaction temperature in degrees Celsius atwhich the batch is held until crystallization is complete;and A, B, C,D, E, F, G, H, I, J and K are constants having the following values:

    ______________________________________                                        A = -0.14827        F = -3.31907                                              B = 0.11922         G = -0.50955                                              C = -0.03245        H = 0.00532                                               D = 0.59054         I =  0.12626                                              E = -0.10945        J = -0.76339                                                                  K = 5.40831;                                              ______________________________________                                    

and provided further that said surface areas of greater than about 10 m²/g are obtained by selecting said molar ratios and reaction temperaturefromthe values provided so that the measured surface area is a functionof synthesis conditions and is expressed mathematically by the followingequation:

    ______________________________________                                        Surface area, m.sup.2 /g =                                                                 A(H.sub.2 O/Na.sub.2 O) + B(Na.sub.2 O/SiO.sub.2) +                           C(SiO.sub.2 /Al.sub.2 O.sub.3).sup.2 + D(SiO.sub.2 /Al.sub.2                  O.sub.3).sup.3 +                                                              E(Temp).sup.2 + F(H.sub.2 O/Al.sub.2 O.sub.3) +                               G(H.sub.2 O/Al.sub.2 O.sub.3).sup.2 + H(H.sub.2 O/Al.sub.2                    O.sub.3).sup.3 +                                                              I(H.sub.2 O/Na.sub.2 O × Temp) + J(SiO.sub.2 /Al.sub.2                  O.sub.3 ×                                                               Temp) + K(H.sub.2 O/Na.sub.2 O ÷ Na.sub.2 O/SiO.sub.2)                    +                                                                             L(H.sub.2 O/Na.sub.2 O ÷ SiO.sub.2 /Al.sub.2 O.sub.3) +                   M(Na.sub.2 O/SiO.sub.2 ÷ SiO.sub.2 /Al.sub.2 O.sub.3)        ______________________________________                                                     +N                                                           

wherein:

    ______________________________________                                        A =     -57.11009845  H =     2.6067484 × 10.sup.-5                     B =    -113.11000549  I =     0.13123613                                      C =     -65.39277171  J =     1.86829830                                      D =      4.76134125   K =     33.33057224                                     E =     -0.04384689   L =     14.30545704                                     F =      9.69234350   M =     93.07457393                                     G =     -0.02585795   N =    233.29360457                                     ______________________________________                                    

H₂ O=Total moles of H₂ O in the batch Na₂ O=Total moles of Na₂ O in thebatch SiO₂ =Total moles of SiO₂ in the batch Al₂ O₃ =Total moles of Al₂O₃ in the batch Temp.=Temperature in degrees Celsius at which the batchis held until crystallization is complete.
 3. A rubber compositionaccording to claim 1 wherein the rubber is a natural or syntheticrubber.
 4. A rubber composition according to claim 3 wherein the rubberis an elastomer.
 5. A rubber composition according to claim 3 whereinthe rubber is a natural rubber.